Emerging Trends in The Social and Behavioral Sciences

Why do States Pursue Nuclear Weapons (or Not)

Item

Title

Why do States Pursue Nuclear Weapons (or Not)

Author

Wan, Wilfred

Solingen, Etel

Research Area

Social Processes

Topic

International Relations

Abstract

This essay traces the evolution of the literature on the rationale behind states' pursuit of nuclear weapons, from classical neorealist explanations focusing on relative power to neoliberal institutionalist ones underlining the deterrent power of institutions and constructivist work on the impact of norms, status, and identities. We call attention to their contributions as well as their conceptual and empirical deficiencies and introduce an approach that links both nuclear ambition and nuclear restraint to models of domestic political survival. The inclusion of this previously overlooked independent variable harnesses the utility of extant approaches, allowing more effective weighing of the impact of other causal variables, while accounting for variation over time, across and within states. We take stock of more recent work employing quantitative and qualitative approaches and identify an agenda for advancing causal theories explaining why some states pursue nuclear weapons whereas others do not.

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etrds0386

extracted text

Why do States Pursue Nuclear
Weapons (or Not)
WILFRED WAN and ETEL SOLINGEN

Abstract
This essay traces the evolution of the literature on the rationale behind states’ pursuit of nuclear weapons, from classical neorealist explanations focusing on relative
power to neoliberal institutionalist ones underlining the deterrent power of institutions and constructivist work on the impact of norms, status, and identities. We call
attention to their contributions as well as their conceptual and empirical deficiencies
and introduce an approach that links both nuclear ambition and nuclear restraint
to models of domestic political survival. The inclusion of this previously overlooked
independent variable harnesses the utility of extant approaches, allowing more effective weighing of the impact of other causal variables, while accounting for variation
over time, across and within states. We take stock of more recent work employing
quantitative and qualitative approaches and identify an agenda for advancing causal
theories explaining why some states pursue nuclear weapons whereas others do not.

INTRODUCTION
What are the driving forces behind state decisions to pursue nuclear
weapons, to reverse course in their quest, or to reject them altogether?
Since the onset of the nuclear age, a breadth of scholarship has detailed the
incentives and disincentives that account for nuclear behavior, including
security, status/prestige, cost, technical difficulties, and domestic and international opposition. Single-country historical accounts and policy-oriented
studies dominated the first phase of this literature. This tendency placed
some limits on generalizability, given the modest number of cases and data
restrictions during the Cold War. Theoretical analysis was relatively limited
and circumscribed to balance of power theory, known also as neorealism. The
1990s witnessed efforts to broaden the theoretical repertoire and transcend
monocausal explanations, challenging the dominant neorealist paradigm
(Lavoy, 1993; Ogilvie-White, 1996; Sagan, 1996; Solingen, 1994a, 1994b). This

Emerging Trends in the Social and Behavioral Sciences. Edited by Robert Scott and Stephen Kosslyn.
© 2015 John Wiley & Sons, Inc. ISBN 978-1-118-90077-2.

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trend, however, also led to contestation regarding the main causal drivers
for acquiring nuclear weapons or abstaining from doing so.
We begin by exploring three main approaches: neorealism, neoliberal institutionalism, and constructivism. We acknowledge the important insights
each provides but also raise some conceptual difficulties; the empirical
record further challenges their validity and generalizability. The study of
proliferation pathways requires a degree of analytical flexibility not afforded
by these extant theories in isolation. A fuller understanding of nuclear
decisions requires a framework able to estimate whether, when, and how
relative power, international institutions, and norms weigh on different
cases. We introduce an approach pivoted on domestic political survival
models capable of endogenizing those variables, a framework applicable to
the universe of cases (Solingen, 1994a, 1994b, 2007). Our final section raises
challenges for future research.
THEORETICAL EVOLUTION OF THE FIELD
NEOREALISM
Neorealist theory provided the conventional explanation for nuclear
behavior: the absence of an ultimate authority above the sovereign state
perpetuates a purely competitive international structure, leading states to
the “individualistic pursuit of security,” “self-help,” and balance of power
(Dunn, 1982; Jervis, 1982; Rosecrance, 1964; Waltz, 1981). The pursuit of
nuclear weapons, accordingly, is an imperative of state survival in an
anarchic world. But, why have so many states abdicated that canon? External insecurity has proven an insufficient condition for nuclear weapons’
acquisition (Betts, 2003). Egypt, South Korea, Jordan, Taiwan, and Japan,
all ultimately eschewed nuclear weapons, even as their rivals acquired or
developed them. Some neorealist scholars invoke the role of alliances in
explaining anomalies (Paul, 2000). Yet, the evidence for that is similarly
mixed. The absence of alliances and hegemonic guarantees did not prevent
states from reversing nuclear ambitions, as with Egypt, Libya, South Africa,
Argentina, and Brazil. Conversely, coercive action by the United States and
the Soviet Union did not stop North Korea, India, Pakistan, or Israel from
weapons’ acquisition. The putative structural trap may be less confining
than stipulated by neorealism: states opt for different solutions—nuclear
and nonnuclear—to comparable security predicaments.
Such inconsistencies in the empirical record are compounded by fundamental conceptual difficulties, including elastic and subjective definitions
of vulnerability and power (Haas, 1953). A focus on “threats” (Walt, 1987)
draws attention away from systemic consideration, squarely on which

Why do States Pursue Nuclear Weapons (or Not)

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domestic actors define what constitutes a threat. Crucially, neorealist theory
is underdetermining, allowing for multiple possible outcomes: state survival might be secured by a wide range of behavior. Nuclear weapons may
enhance or undermine security. The thresholds explaining nuclearization
are unclear at best: power differentials lead to open-ended operational
implications ranging between abstention and acquisition.
These deficiencies raise a fundamental analytical and methodological consideration.
High national security is the arena where neorealism should perform
best, its home court, easy grounds for testing theories of balance of power
and state security under anarchy. Nuclear weapons are at the heart, the
inner sanctum of states’ security dilemmas. This is the theory’s most auspicious domain for corroborating its tenets, loading the dice in its favor.
Further, leaders, politicians, and bureaucrats are more likely to portray
decisions for or against nuclear weapons as dictated by “state survival”
rather than domestic political expediency or other factors. The evidentiary
record—public and private—thus tilts the analysis toward an already
privileged theoretical driver. All these considerations magnify the weight of
empirical anomalies.
A theory that cannot be easily confirmed at high levels of confidence, even
under the best circumstances, compels serious rethinking. Nuclear outcomes
are clearly not the sole perfunctory reflection of international power structure.
NEOLIBERAL INSTITUTIONALISM
The neoliberal institutionalist school of thought emerged to challenge
neorealist assumptions regarding cooperation, questioning the rigidity and
severity of the self-help world, and offering institutions as the means to
reduce conflict (Jervis, 1999). Institutions provide an attractive alternative
to the unilateral pursuit of security: they lower transaction costs, enhance
information about preferences and behaviors, monitor compliance, detect
defections, and foster repeated and continuous interactions between states
(Axelrod & Keohane, 1985; Keohane, 1984; Lipson, 1984; North, 1981). Their
presence constrains state behavior, altering strategies and beliefs over outcomes. Significantly, the nuclear arena boasts one of the most prominent and
long-lasting international institutions. The Treaty on the Nonproliferation
of Nuclear Weapons (NPT) has become the center of an encompassing
regime that includes organizations (e.g., the International Atomic Energy
Agency [IAEA]), negotiating forums (Conference on Disarmament), consortiums (Nuclear Suppliers Group), and nested treaties (Comprehensive Test
Ban Treaty, Nuclear-Weapon-Free Zones) (Wan, 2014b). The International

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Atomic Energy Agency safeguards agreements in place under the NPT aim
to prevent the diversion of materials from peaceful nuclear activities to
weapons programs, while the 1997 optional Additional Protocol expanded
the range of information submitted by the states and granted the IAEA
complementary access for verification. As Nye argued (1988, p. 336), “That
most states adhere to a regime in which they foreswear the right to use the
ultimate form of self-help in technological terms is quite an extraordinary
situation.”
Placed under closer scrutiny, however, a narrative that links the NPT
regime to the nuclear decisions of states––as in the work of Walsh
(2005)––encounters myriad difficulties. While it is reasonable to presume that states join international institutions with an eye on absolute
(rather than relative) gains, the extent to which that presumption has held in
this arena is questionable and fundamentally understudied empirically. The
durability of the NPT regime masks long-standing discord regarding the
central bargain. There is widespread belief among nonnuclear weapon states
that the NPT does not represent “collective interests, but rather [serves] as
an instrument utilized by the major powers … to constrain and discipline
other states” (Miller, 2012, pp. 8–9). Further, challenges posed by nonstate
actors, by noncompliance with safeguards, and by enforcement issues
undermine the image that the regime fulfills the promise of international
institutions (Braun & Chyba, 2004; Goldschmidt, 2009). Beyond all that, we
do not yet have a systematic empirical foundation that would allow us to
ascertain whether or not the NPT regime has played a central role in the
nuclear behaviors of states. Selection effects, the reasons that led states to
join the treaty––domestic interests, hegemonic coercion, and others––may
in fact explain subsequent compliance (and the rejection of nuclearization)
better than the NPT itself. As Guzman (2008, p. 80) suggests, “for many
[parties] … one would expect compliance even in the absence of a treaty.”
As with neorealism, neoliberal institutionalism encounters very significant
difficulties when considering causal processes, including the sequence,
effect, and mechanisms connecting regime membership to nuclear weapons’
renunciation.
CONSTRUCTIVISM
While earlier work explored the ethics of nuclear weapons (Hardin, Goodin,
Mearsheimer, & Dworkin, 1985; Nye, 1986), the constructivist wave intensified the consideration of norms, status, and identity in the non/pursuit
of weapons of mass destruction (Husbands, 1982; Tannenwald, 2005, 2007).
From this perspective, the significance of the NPT regime does not center
on its ability to reduce transaction costs or other rationalistic considerations.

Why do States Pursue Nuclear Weapons (or Not)

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Rather, international institutions and norms are sociological phenomena
reflecting and imprinting the collective identities of member states, changing
actors’ beliefs and identities, and altering the very definition of interests
(Finnemore & Sikkink, 1998; Johnston, 2001; Klotz & Lynch, 2007; March &
Olsen, 1998). Institutions “constitute and construct the social world” (Barnett
& Finnemore, 1999, p. 700). The NPT regime, in this view, stems from the evolution of antinuclear weapons norms embedded in the centerpiece treaty. The
regime socialized nuclear and nonnuclear bureaucracies, created new expectations and habits, and transformed states’ beliefs about the ethical status of
nuclear weapons, thereby leading to near-universal compliance. Overall, it
stands as a constellation of entities that restrict freedom of action on nuclear
matters and has contributed to the emergence of a taboo defining nuclear
weapons as unconventional, abhorrent, and unacceptable (Schelling, 2000).
Yet, evidence for the norm against acquisition of nuclear weapons is far
more questionable than a norm against their use (Solingen, 2007; Walker,
2010). Weapons development has spanned more than half a century in
the aftermath of the Manhattan Project, from the first Soviet nuclear test
in 1949 to the most recent North Korean test in 2013 ; the consideration
of nuclear weapons by Sweden, Norway, Yugoslavia, Switzerland, and
others also questions the existence of a taboo. There are too many anomalies
throughout the life span of the NPT, with another 15 states seeking to
acquire weapons-related capabilities through the 1990s and several cases
of noncompliance with safeguards in the early 2000s in Iran, Libya, South
Korea, and Egypt. Very mild international responses to India and Pakistan’s
1998 tests further undermine the argument of a prohibition taboo, as do more
recent discussions of new nuclear claimants such as Saudi Arabia and others.
Nuclear weapons have not been “unthinkable” even in Japan, a “crucial” case for antinuclear norms, given the experiences of Hiroshima and
Nagasaki. Japan’s pacifist movement sensitized its leaders to domestic
opposition to nuclear weapons, but this was only one strand in Japan’s
public opinion. The very conduct of several government studies on Japan’s
nuclear options suggests that nuclear weapons’ acquisition—although
unlikely—was less than a taboo (Okimoto, 1978). Public opinion polls suggest that the “nuclear allergy” was much stronger subsequently than during
the first two decades of the postwar era, when historic nuclear decisions
were under consideration (Solingen, 2010). Japan delayed ratification of NPT
by nearly 7 years, which stood in contrast with its sustained support for UN
multilateralism in the postwar era. While domestic institutional restraints
such as the Atomic Energy Law and the Three Nonnuclear Principles had
significant force, there was also continuous contestation over interpretations
of Article IX of the Constitution (renouncing the right of belligerency without
referring to nuclear weapons), which may explain why the Principles never

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became law (Chai, 1997). Even the reliance on the US nuclear umbrella was
not precisely a policy suggestive of nuclear abstinence. Compromises over
US introduction of nuclear weapons into Japan were also an expression
of what opponents of nuclear weapons considered akin to “embedded
nuclearization.” As Mochizuki (2006) argued, “Japan’s pacifism has always
been pragmatic.”
All these cases, and continued expectations of nuclear dominoes in the
Middle East and Asia—responsive to nuclearized Iranian or North Korean
threats—continue to question the existence of a taboo against acquisition.
United Nations Secretary-General Kofi Annan suggested in 2006 that many
states were revisiting their logic on the issue of nuclear weapons (Broad &
Sanger, 2006). As with the other theories, conceptual, methodological, and
empirical problems plague the normative/sociological account.
DOMESTIC MODELS OF POLITICAL SURVIVAL (MPS)
The three preceding theoretical frameworks share a fundamental inattention to an important omitted variable: domestic political drivers. In a
study of Taiwan, Bueno de Mesquita, Morrow, and Wu (1993) argued that
nuclear behavior is necessarily linked to a supportive domestic coalition.
This was a progressive move away from both underdetermining systemic
balance of power considerations and a reductionist focus on treaties, taboos,
and arguments focused on individual leaders as single-handedly driving
outcomes. Yet, coalitions come in many forms; the microfoundations of
why some coalitions might support the acquisition of nuclear weapons
(whereas others might not) remained undertheorized. Focusing on the
domestic distributional consequences of integration in the global political
economy as a point of departure, Solingen (1994a, 1994b) identified two
ideal-typical coalitions, advancing competing models of political survival
(MPS) in power. These models entailed not simply different orientations to
the global political economy and associated economic, political, and security
institutions; they also had different implications for nuclear choices in the
aftermath of the 1970 inception of the NPT.
While nuclear proliferation and political economy had been highly segregated fields of inquiry, “The Political Economy of Nuclear Restraint,”
published in International Security in 1994, foregrounded the linkages
between the two along the following lines: Internationalizing coalitions
advocating economic growth through integration in the global economy
had incentives to avoid the domestic and international, political and economic (including opportunity) costs of embarking on nuclear weapons
programs. They were more receptive to renouncing nuclear weapons for
several synergistic reasons: to enhance their appeal to foreign investors,

Why do States Pursue Nuclear Weapons (or Not)

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signaling a commitment to economic growth and stability; to reassure
neighbors and boost regional cooperation, stability, and attractiveness; to
secure access to international markets for exports, capital, technology, and
raw materials; to avoid incurring reputational losses at home and abroad
for uncertain nuclear gains; and to avoid alienating domestic agents of
internationalization that might be adversely affected by nuclear weapons
development. Such weapons, in other words, would burden efforts to
enhance exports, economic competitiveness, macroeconomic and political
stability, and global access, all objectives of internationalizing models, and
would strengthen adversarial state bureaucracies and industrial complexes
opposed to economic openness.
Inward-looking coalitions had greater tolerance—and sometimes strong
incentives—to develop nuclear weapons. Nuclearization entailed fewer
costs for political platforms rooted in mistrust for international markets, investment, technology, and institutions. Backed by protected and
uncompetitive national industries, sprawling state enterprises and ancillary military–industrial and nuclear complexes, foes of internationalizing
models benefited from import substitution, nationalism, and claims of
self-sufficiency. They thus had greater incentives to exploit nuclear weapons
as tools in inward-looking platforms of political competition and survival;
often relied on extreme language to compel and threaten regional adversaries; misled or violated international nonnuclear commitments; and were
more promiscuous regarding state-directed or state-endorsed dissemination
of sensitive nuclear technologies as sources of financing inward-looking
models.
Thus, whereas nuclear weapons programs may have been assets in the
arsenal to build inward-looking regime legitimacy, they were drawbacks for
outward-oriented models.
These hypothesized patterns of nuclear behavior find support from
systematic observations in the Middle East, East Asia, and beyond across
different regional security contexts, diverse associations with hegemonic
powers, and over successive leaderships within the same state. Heavy
regional concentration of internationalizing models in East Asia since the
1970s reinforced each state’s incentives to avoid nuclearization. Conversely,
heavy regional concentration of nationalist, protectionist, and militarized
models throughout the Middle East exacerbated mutual incentives to
develop nuclear weapons. Considering the relevant universe of cases
where nuclear weapons were entertained or launched over the last four
decades, not one endorsed denuclearization––fully and effectively––under
inward-looking models. Only internationalizing coalitions undertook
effective commitments to eschew nuclear weapons, from Egypt (under
Sadat) to South Africa, Brazil, Argentina, Japan, Taiwan, South Korea,

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

Spain, and Libya in 2003. Most defiant nuclear courses were associated with
inward-looking models, from Argentina under Perón (Liberación o Muerte) to
North Korea (juche), India (swadeshi), and equivalents in Pakistan, Nasser’s
Egypt, Iraq, Iran, and Libya pre-2003. The pace and timing of renunciation
was nested in broader shifts toward internationalization in economics
and security. Where internationalizing models were stronger politically,
departures from nuclear claims were sustained even where the security
context remained challenging, as in Japan, South Korea, and Taiwan. Weaker
internationalizing coalitions in Iran, Pakistan, and Argentina and Brazil until
the 1990s were more politically constrained in curbing nuclear programs. A
model’s relative regional incidence influenced nuclear decisions more than a
neighbor’s nuclearization per se.
These MPS help explain why different actors within the same state diverge
in their approaches and preferences regarding nuclear policy; why a state’s
nuclear policies may vary over time as a function of the relative power of
particular domestic forces; why different states vary in their commitments
to increase information, transparency, and compliance with international
commitments; why security dilemmas are sometimes seen as more (or
less) obdurate; why some states rank alliances higher than self-reliance
but not others; when and how hegemonic coercion and inducements are
effective and when they play a secondary or marginal role; why nuclear
weapons’ programs surfaced where there was arguably little need for them
(the Southern Cone or South Africa among others); and why such programs
were obviated where one might have expected them (Vietnam, Singapore,
Jordan, and many others).
The omission of this significant independent variable in first-generation
studies may have led to an overestimation of other causal variables (balance
of power, institutions, norms) and to potential spurious effects. Its inclusion
may improve our understanding of the actual effects of security dilemmas,
international norms, and institutions. This is different from arguing that MPS
are the only relevant variable; only that MPS enable a better understanding
of the relative impact of other variables on nuclear choices. Indeed, several
empirical studies have provided support for a MPS framework (Liberman,
2001; Solingen, 2004, 2007). Potter and Mukhatzhanova (2008, 2010) endorsed
its caution in overestimating the effects of any single causal variable and
its solid grounding in comparative field research and social science theory.
They found it particularly persuasive in accounting for much of the variation over time across and within states. For instance, internationalizing coalitions relinquished the nuclear option even in the absence of alliances (Egypt,
South Africa, Argentina, Brazil). The centrality of MPS is especially notable
since the evidentiary dice (archives, statements, etc.) is loaded against ulterior domestic political justifications. Leaders have incentives to cast decisions

Why do States Pursue Nuclear Weapons (or Not)

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favoring or rejecting nuclear weapons as “reasons of state” invoking national
security, international institutional incentives, or normative considerations.
Hence, whereas nuclear behavior provides neorealism with “most likely”
conditions for supporting its tenets, it offers “least likely” conditions for corroborating a MPS argument. Consequently, empirical support for findings
along these lines gains particular significance in this unfriendly terrain.
MPS may not capture all the correlates of nuclear preferences and are, after
all, only ideal types, conceptual constructs rather than historical or “true”
realities. As such, they need not fit every case or indeed any particular case
completely (Eckstein, 1975), but rather provide a heuristic, a helpful shortcut, and a fruitful comparative framework capable of reducing a complex
reality down to some fundamentals. Propositions derived from a MPS framework remain bounded in three ways: with respect to conditions of necessity
and sufficiency in developing nuclear weapons; the incidence of compatible
models in the region; and temporal sequences in the acquisition of nuclear
weapons. Eliminating existing weapons may be more costly politically than
eradicating precursor programs, as stipulated by prospect theory, and the
incentives emanating from the global political economy may operate more
forcefully both at earlier stages in the inception of internationalizing models
and earlier stages in the consideration of nuclear weapons. These hypotheses
remain subject to further investigation.
RECENT RESEARCH DEVELOPMENTS
There has been a significant shift across the methodological range toward
theorizing and testing the role of domestic political drivers to a much greater
extent than was the case two decades ago. The international relations theory
toolkit for studying nuclear decision-making is far more sophisticated theoretically and more diverse methodologically. However, it still suffers from
weak efforts to rely on complementary methods, to explore linkages across
perspectives, and to envisage scope conditions for the operation of different
variables across time and space. The absence of a more analytically eclectic
approach (Sil & Katzenstein, 2010) has hindered the field as a whole, with
works too often speaking past rather than building on one another.
In particular, the last decade has witnessed the newfound application of
quantitative methods to gauge the nuclear motivations of states. Jo and
Gartzke (2007, p. 186) downplay the general role of domestic political
factors––regime type plays no role in the initial decision to nuclearize. Their
study is in many ways an affirmation of the neorealist argument: states’
willingness to seek nuclear weapons is linked to “external concerns,” and
especially to “countervail conventional disadvantage.” Singh and Way
(2004) not only similarly highlighted the external threat environment, but

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also found support for the propositions that “the process of economic
liberalization is associated with a reduced likelihood of exploring nuclear
weapons;” that “economic openness has a statistically significant negative
effect across all three levels of proliferation” (i.e., exploring, pursuing, or
acquiring them); and that “economic liberalization dampened the risk” of
states deciding “to explore seriously the nuclear option” (pp. 876, 878). This
study also recognizes that the connection might have been even stronger,
had cases of states that abandoned nuclear programs been included. Also
excluded were prospective efforts to enhance economic openness and attract
foreign investment, which are the crucial drivers in MPS arguments. There is
no one-to-one correspondence between incentives and efforts to open up the
economy at time T and measures of trade openness at T+1. Fuhrmann and
Li (2008) found that economic liberalization had a positive and statistically
significant effect on nuclear-weapon-free zone treaty ratification as well.
Yet, the process by which those treaties emerge suggests the possibility of
selection effects.
Overall, the quantitative turn has done little to settle debates regarding
state motivations to acquire or renounce nuclear weapons. Given their
disparate findings, the diversity of datasets, coding rules, and statistical methods has only served to muddle the waters; furthermore, the
operationalization of variables failed to capture the nuance of some theories,
undermining the robustness of their conclusions (Montgomery & Sagan,
2009; Sagan, 2011). Many studies, for instance, rely on the Composite Index
of National Capabilities in order to measure state power. Yet, such an
operationalization obscures the subjectivity inherent in notions of power,
overlooking the role of different domestic actors in shaping the definition
and perception of threats. The notion of institutional effects is oftentimes
reduced to NPT membership, severely underrepresenting the depth of the
nonproliferation regime. The negative correlation between existing levels
of trade openness and nonproliferation in some studies is curious, but
quantitative studies are ill-suited to make causal claims about the nature of
ruling coalitions, their expected utilities, the crucial role played by regional
coalitional homogeneity/heterogeneity, and the implications of all these for
the pursuit or renunciation of nuclear weapons.
Several recent works have infused social psychology into the study of
proliferation, following the broader constructivist turn in international
relations theory. Long and Grillot’s (2000) overview of South African and
Ukrainian denuclearization argued that causal beliefs about their respective
Western identities played “a significant role both in preference formation
and strategic choice regarding nuclear policymaking” (p. 36). However, the
conceptualization of these causal beliefs appears overly deterministic and

Why do States Pursue Nuclear Weapons (or Not)

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inflexible, hardly allowing for the possibility of domestic dissension regarding those identities. South Africa’s Western identity was firmly in place
by the 1940s, they argue, with only slight fluctuations subsequently, while
Ukranian leaders simply began asserting Ukraine’s status as a European
state after independence. Hymans (2006) linked the individual identity of
state leaders—“oppositional nationalists” —with the drive toward nuclear
weapons’ ambitions. Yet, individual psychology as a causal factor presents
significant methodological challenges, including accurate assessment of
the leaders’ presumed profiles. For instance, Japan’s nonnuclear status is
often—wrongly—traced to Premier Sato’s putative antinuclear weapons
commitments (he received the Nobel Prize on that account). But, declassified
records suggest otherwise: Sato conveyed to US Ambassador Reischauer
a personal preference for a nuclear Japan in 1964, oversaw a confidential
inquiry into possible distinctions between offensive and defensive nuclear
weapons in 1967 (the latter allowed by Japan’s constitution according to
some readings), and declared in a 1969 meeting with business leaders that a
defense system was incomplete “if we cannot possess nuclear weapons in
the era of nuclear weapons” (Solingen, 2007, p. 73).
Further exploration of the Japanese case demonstrates the empirical fallacies of attributing nuclear policy to individual psychology. The confluence
of major systemic triggers (North Korea’s repeated nuclear and missile tests,
the rise of China, conflict over the Senkaku/Diaoyu and Takeshima/Dokdo
islands) and strong conservative leaders at Japan’s helm have not yielded
the shifts expected by personality—or neorealist—variables (Mearsheimer,
1981). The succession of a large number of premiers over decades—with a
wide range of personalities and psychological identities—has yielded the
same outcome thus far. This includes the “most-likely” (ideational) cases
of Premiers Fukuda Yasuo, Aso Taro and Abe Shinzo, the latter an ardent
conservative nationalist at heart who learned about Japanese strategic
options at his grandfather’s (Kishi’s) knee. Yet, he did not move Japan
beyond the nonnuclear principles in his first term or even his second, after
North Korea tested nuclear weapons three times, once under his watch.
Abe reaffirmed Japan’s nonnuclear status, aware of the economic, political,
regional, and global requirements without which Japan’s survival in the
twenty-first century global political economy could not be guaranteed.
Such deficiencies of personality-based approaches led Rublee (2009) to link
nuclear forbearance to the international social environment, highlighting
mechanisms of persuasion, social conformity, and identification. Yet, despite
her acknowledgment that “some segments of a state may be more susceptible than others” (p. 5), her treatment of domestic politics remains imprecise.
The discussion of social costs can also obscure the connection of nuclear
issues to other domestic concerns, leading to seemingly inconsistent policies

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that are more difficult to reconcile with identity-based factors. For instance,
despite Sato’s chronicled private inclinations toward nuclear weapons’
acquisition, his foremost political purpose was Okinawa’s reversion to
Japan––a goal he was prepared to advance even if it meant accepting the
formal adoption of the nonnuclear principles in exchange for the Diet’s
approval of his Okinawa agreement. As available historical data suggest,
political survival models and “audience costs” considerations appear to
have neutralized other proclivities that Kishi, Yoshida, Sato, Nakasone,
Aso, or others have had and expressed publicly. Ultimately, the ideational
qualitative studies vary in the extent to which they contend seriously with
competing hypotheses and are amenable to systematic testing.
THE AGENDA AHEAD
The classic perspectives remain very much part of the menu in the study
of nuclear behavior. However, a future agenda should move beyond
indeterminacy, tautologies, or posthocism. Studies along neorealist lines
must cast their arguments precisely and in falsifiable terms; grapple with
more precise notions of power and vulnerability; further stipulate the
impact of alliances and hegemonic guarantees; and specify threshold
conditions for nuclear breakout. Given their systemic assumptions, they
must explain variation in nuclear behavior independently of domestic or
other auxiliary considerations extraneous to structural (relative) power.
Studies advancing neoliberal institutionalist perspectives must expand the
empirical base for stipulating causal linkages between regime membership
and nuclear decisions; address the problem of selection effects through
counterfactual analysis of decisions in a hypothetical environment free of
NPT commitments; and reconcile the presumption of Pareto-optimality
with the reality of power hierarchies in the NPT (Wan, 2014a). Constructivist work must distinguish across nuclear norms (acquisition, use, etc.);
explain the resilience of advocacy for nuclear weapons in nuclear weapons
states and some nuclear aspirants; improve our understanding of selective
socialization into antinuclear weapons norms; explain clustered regional
behavior toward or away from nuclearization under the shadow of the
same international norm (or, why has the norm diffused selectively); and
complement normative accounts of nuclear weapons’ acquisition or rejection
with a theory of domestic politics (or, what explains domestic receptivity
to some norms but not others) that may explain barriers to norm diffusion.
Political survival models must improve classification of coalitions along the
internationalizing/inward-looking spectrum; estimate thresholds beyond
which coalitional shifts might overturn a trajectory toward or away from
nuclear weapons (in other words, when can path-dependence dominate

Why do States Pursue Nuclear Weapons (or Not)

13

coalitional tendencies); and consider the impact of world-time––and an
evolving global economy––on the character of coalitions.
Analysis of nuclear behavior that is attentive to complexity—interaction
among variables—and to historical context can enhance both historical accuracy and predictive capabilities. As Philip Tetlock’s (2005) masterful treatise
on expert political judgment and prediction suggests, parsimony can be the
enemy of accuracy, a substantial liability in real-world forecasting. Quantitative work should be more attentive to the inclusion of relevant cases only
(Cape Verde does not add much validity to a database on this topic); improve
the fit between variables and conceptual arguments; harmonize databases;
and integrate more recent and sophisticated arguments from the overarching international relations toolkit. Qualitative studies should improve the
criteria for case selection, seeking crucial cases and least likely conditions
that force the empirical analysis to overcome difficult conditions. Cases that
feature a reversal of course in either direction seem especially fruitful analytically, the various periods of fluctuation enhancing the number of observations and the opportunity to gauge variation over time. Nuclear outcomes
may be conceptualized not as finite and final but as malleable and operating
on a continuum.
One may find an approach reasonably persuasive in explaining the past, but
it does not necessarily follow that it will also apply in the future. Nonetheless, causal theories must be able to lay out a priori what kind of evidence
would question or corroborate their expectations. They must avoid suggesting many outcomes that would all be consistent with one particular value
of their key variable, to elude the problem of multifinality. Clarity is a sine
qua non for avoiding circularity and ex post facto rationalizations (such as
“state x went nuclear because of acute insecurity,” whereby a nuclear test is
used to signal a posteriori, retroactively, that an acute threshold of insecurity
has been crossed). Arguments must be cast in falsifiable terms a priori, with
more clearly defined and testable propositions. Sensitivity to these and other
conceptual and methodological issues described above can lead to analytical progress and offer better policy insight on the processes and mechanisms
that drive the nuclear behaviors of states.
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Goldschmidt, P. (2009). Exposing nuclear non-compliance. Survival, 51(1), 143–164.
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Hymans, J. E. C. (2006). The psychology of nuclear proliferation: Identity, emotions and
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Klotz, A. J., & Lynch, C. M. (2007). Strategies for research: In constructivist international
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26(2), 45–86.
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Potter, W. C., & Mukhatzhanova, G. (Eds.) (2010). Forecasting nuclear proliferation
in the 21st century. Stanford, CA: Stanford Security Studies/Stanford University
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York, NY: Columbia University Press.
Rublee, M. R. (2009). Nonproliferation norms: Why states choose nuclear restraint. Athens,
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Sagan, S. D. (1996). Why do states build nuclear weapons? Three models in search of
a bomb. International Security, 21(3), 54–86.
Sagan, S. D. (2011). The causes of nuclear weapons proliferation. Annual Review of
Political Science, 14(1), 225–244.
Schelling, T. (2000). A half-century without nuclear war. The Key Reporter, 65(3), 3–5.

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Sil, R., & Katzenstein, P. J. (2010). Beyond paradigms: Analytic eclecticism in the study of
world politics. New York, NY: Palgrave Macmillan.
Singh, S., & Way, C. R. (2004). The correlates of nuclear proliferation: A quantitative
test. The Journal of Conflict Resolution, 48(6), 859–885.
Solingen, E. (1994a). The domestic sources of regional regimes: The evolution
of nuclear ambiguity in the Middle East. International Studies Quarterly, 38(2),
305–337. doi:10.2307/2600979
Solingen, E. (1994b). The political economy of nuclear restraint. International Security,
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Solingen, E. (2004). Southeast Asia in a new era: Domestic coalitions from crisis to
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weapons since 1945. New York, NY: Cambridge University Press.
Tetlock, P. (2005). Expert political judgment: How good is it? how can we know? Princeton,
NJ: Princeton University Press.
Walker, W. (2010). The absence of a taboo on the possession of nuclear weapons.
Review of International Studies, 36(4), 865–876.
Walsh, J. (2005). Learning from past success: The NPT and the future of non-proliferation
(pp. 1–65 (No. 41)). Stockholm, Sweden: Weapons for Mass Destruction Commission.
Walt, S. M. (1987). The origins of alliance. Ithaca, NY: Cornell University Press.
Waltz, K. N. (1981). The spread of nuclear weapons: More may be better. London, England:
International Institute for Strategic Studies.
Wan, W. (2014a, forthcoming). Firewalling nuclear diffusion. International Studies
Review, 16(2).
Wan, W. (2014b, forthcoming). Security institutions and change: The nuclear nonproliferation regime in crisis (ms.)

FURTHER READING
Potter, W. C., & Mukhatzhanova, G. (Eds.) (2010). Forecasting nuclear proliferation
in the 21st century. Stanford, CA: Stanford Security Studies/Stanford University
Press.
Sagan, S. D. (2011). The causes of nuclear weapons proliferation. Annual Review of
Political Science, 14(1), 225–244.
Solingen, E. (2007). Nuclear logics: Contrasting paths in East Asia and the Middle East.
Princeton, NJ: Princeton University Press.

Why do States Pursue Nuclear Weapons (or Not)

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WILFRED WAN SHORT BIOGRAPHY
Wilfred Wan is a Japan Society for the Promotion of Science-United
Nations University Postdoctoral Fellow working with the UNU Centre
for Policy Research in Tokyo. He was a 2013–2014 Social Science Research
Council–JSPS Postdoctoral Fellow at Hitotsubashi University. He spent 2
years as a predoctoral fellow with an International Security Program and
Project on Managing the Atom joint appointment at the Belfer Center for
Science and International Affairs (Harvard Kennedy School), including one
as a Stanton Nuclear Security Fellow. He is also a former Institute on Global
Conflict and Cooperation Dissertation Fellow. He has co-authored a chapter
in Sanctions, Statecraft, and Nuclear Proliferation (Cambridge University
Press).
ETEL SOLINGEN SHORT BIOGRAPHY
Etel Solingen is the Thomas T. and Elizabeth C. Tierney Chair in Peace Studies at the University of California Irvine and former UCI Chancellor’s Professor and President of the International Studies Association. Her book Nuclear
Logics: Contrasting Paths in East Asia and the Middle East (Princeton U.P.)
received the APSA’s 2008 Woodrow Wilson Foundation Award for the best
book in all fields and the 2008 APSA’s Robert Jervis and Paul Schroeder
Award for the best book on International History and Politics.
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Constitutionalism (Political Science), Keith E. Whittington



Why do States Pursue Nuclear
Weapons (or Not)
WILFRED WAN and ETEL SOLINGEN

Abstract
This essay traces the evolution of the literature on the rationale behind states’ pursuit of nuclear weapons, from classical neorealist explanations focusing on relative
power to neoliberal institutionalist ones underlining the deterrent power of institutions and constructivist work on the impact of norms, status, and identities. We call
attention to their contributions as well as their conceptual and empirical deficiencies
and introduce an approach that links both nuclear ambition and nuclear restraint
to models of domestic political survival. The inclusion of this previously overlooked
independent variable harnesses the utility of extant approaches, allowing more effective weighing of the impact of other causal variables, while accounting for variation
over time, across and within states. We take stock of more recent work employing
quantitative and qualitative approaches and identify an agenda for advancing causal
theories explaining why some states pursue nuclear weapons whereas others do not.

INTRODUCTION
What are the driving forces behind state decisions to pursue nuclear
weapons, to reverse course in their quest, or to reject them altogether?
Since the onset of the nuclear age, a breadth of scholarship has detailed the
incentives and disincentives that account for nuclear behavior, including
security, status/prestige, cost, technical difficulties, and domestic and international opposition. Single-country historical accounts and policy-oriented
studies dominated the first phase of this literature. This tendency placed
some limits on generalizability, given the modest number of cases and data
restrictions during the Cold War. Theoretical analysis was relatively limited
and circumscribed to balance of power theory, known also as neorealism. The
1990s witnessed efforts to broaden the theoretical repertoire and transcend
monocausal explanations, challenging the dominant neorealist paradigm
(Lavoy, 1993; Ogilvie-White, 1996; Sagan, 1996; Solingen, 1994a, 1994b). This

Emerging Trends in the Social and Behavioral Sciences. Edited by Robert Scott and Stephen Kosslyn.
© 2015 John Wiley & Sons, Inc. ISBN 978-1-118-90077-2.

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

trend, however, also led to contestation regarding the main causal drivers
for acquiring nuclear weapons or abstaining from doing so.
We begin by exploring three main approaches: neorealism, neoliberal institutionalism, and constructivism. We acknowledge the important insights
each provides but also raise some conceptual difficulties; the empirical
record further challenges their validity and generalizability. The study of
proliferation pathways requires a degree of analytical flexibility not afforded
by these extant theories in isolation. A fuller understanding of nuclear
decisions requires a framework able to estimate whether, when, and how
relative power, international institutions, and norms weigh on different
cases. We introduce an approach pivoted on domestic political survival
models capable of endogenizing those variables, a framework applicable to
the universe of cases (Solingen, 1994a, 1994b, 2007). Our final section raises
challenges for future research.
THEORETICAL EVOLUTION OF THE FIELD
NEOREALISM
Neorealist theory provided the conventional explanation for nuclear
behavior: the absence of an ultimate authority above the sovereign state
perpetuates a purely competitive international structure, leading states to
the “individualistic pursuit of security,” “self-help,” and balance of power
(Dunn, 1982; Jervis, 1982; Rosecrance, 1964; Waltz, 1981). The pursuit of
nuclear weapons, accordingly, is an imperative of state survival in an
anarchic world. But, why have so many states abdicated that canon? External insecurity has proven an insufficient condition for nuclear weapons’
acquisition (Betts, 2003). Egypt, South Korea, Jordan, Taiwan, and Japan,
all ultimately eschewed nuclear weapons, even as their rivals acquired or
developed them. Some neorealist scholars invoke the role of alliances in
explaining anomalies (Paul, 2000). Yet, the evidence for that is similarly
mixed. The absence of alliances and hegemonic guarantees did not prevent
states from reversing nuclear ambitions, as with Egypt, Libya, South Africa,
Argentina, and Brazil. Conversely, coercive action by the United States and
the Soviet Union did not stop North Korea, India, Pakistan, or Israel from
weapons’ acquisition. The putative structural trap may be less confining
than stipulated by neorealism: states opt for different solutions—nuclear
and nonnuclear—to comparable security predicaments.
Such inconsistencies in the empirical record are compounded by fundamental conceptual difficulties, including elastic and subjective definitions
of vulnerability and power (Haas, 1953). A focus on “threats” (Walt, 1987)
draws attention away from systemic consideration, squarely on which

Why do States Pursue Nuclear Weapons (or Not)

3

domestic actors define what constitutes a threat. Crucially, neorealist theory
is underdetermining, allowing for multiple possible outcomes: state survival might be secured by a wide range of behavior. Nuclear weapons may
enhance or undermine security. The thresholds explaining nuclearization
are unclear at best: power differentials lead to open-ended operational
implications ranging between abstention and acquisition.
These deficiencies raise a fundamental analytical and methodological consideration.
High national security is the arena where neorealism should perform
best, its home court, easy grounds for testing theories of balance of power
and state security under anarchy. Nuclear weapons are at the heart, the
inner sanctum of states’ security dilemmas. This is the theory’s most auspicious domain for corroborating its tenets, loading the dice in its favor.
Further, leaders, politicians, and bureaucrats are more likely to portray
decisions for or against nuclear weapons as dictated by “state survival”
rather than domestic political expediency or other factors. The evidentiary
record—public and private—thus tilts the analysis toward an already
privileged theoretical driver. All these considerations magnify the weight of
empirical anomalies.
A theory that cannot be easily confirmed at high levels of confidence, even
under the best circumstances, compels serious rethinking. Nuclear outcomes
are clearly not the sole perfunctory reflection of international power structure.
NEOLIBERAL INSTITUTIONALISM
The neoliberal institutionalist school of thought emerged to challenge
neorealist assumptions regarding cooperation, questioning the rigidity and
severity of the self-help world, and offering institutions as the means to
reduce conflict (Jervis, 1999). Institutions provide an attractive alternative
to the unilateral pursuit of security: they lower transaction costs, enhance
information about preferences and behaviors, monitor compliance, detect
defections, and foster repeated and continuous interactions between states
(Axelrod & Keohane, 1985; Keohane, 1984; Lipson, 1984; North, 1981). Their
presence constrains state behavior, altering strategies and beliefs over outcomes. Significantly, the nuclear arena boasts one of the most prominent and
long-lasting international institutions. The Treaty on the Nonproliferation
of Nuclear Weapons (NPT) has become the center of an encompassing
regime that includes organizations (e.g., the International Atomic Energy
Agency [IAEA]), negotiating forums (Conference on Disarmament), consortiums (Nuclear Suppliers Group), and nested treaties (Comprehensive Test
Ban Treaty, Nuclear-Weapon-Free Zones) (Wan, 2014b). The International

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

Atomic Energy Agency safeguards agreements in place under the NPT aim
to prevent the diversion of materials from peaceful nuclear activities to
weapons programs, while the 1997 optional Additional Protocol expanded
the range of information submitted by the states and granted the IAEA
complementary access for verification. As Nye argued (1988, p. 336), “That
most states adhere to a regime in which they foreswear the right to use the
ultimate form of self-help in technological terms is quite an extraordinary
situation.”
Placed under closer scrutiny, however, a narrative that links the NPT
regime to the nuclear decisions of states––as in the work of Walsh
(2005)––encounters myriad difficulties. While it is reasonable to presume that states join international institutions with an eye on absolute
(rather than relative) gains, the extent to which that presumption has held in
this arena is questionable and fundamentally understudied empirically. The
durability of the NPT regime masks long-standing discord regarding the
central bargain. There is widespread belief among nonnuclear weapon states
that the NPT does not represent “collective interests, but rather [serves] as
an instrument utilized by the major powers … to constrain and discipline
other states” (Miller, 2012, pp. 8–9). Further, challenges posed by nonstate
actors, by noncompliance with safeguards, and by enforcement issues
undermine the image that the regime fulfills the promise of international
institutions (Braun & Chyba, 2004; Goldschmidt, 2009). Beyond all that, we
do not yet have a systematic empirical foundation that would allow us to
ascertain whether or not the NPT regime has played a central role in the
nuclear behaviors of states. Selection effects, the reasons that led states to
join the treaty––domestic interests, hegemonic coercion, and others––may
in fact explain subsequent compliance (and the rejection of nuclearization)
better than the NPT itself. As Guzman (2008, p. 80) suggests, “for many
[parties] … one would expect compliance even in the absence of a treaty.”
As with neorealism, neoliberal institutionalism encounters very significant
difficulties when considering causal processes, including the sequence,
effect, and mechanisms connecting regime membership to nuclear weapons’
renunciation.
CONSTRUCTIVISM
While earlier work explored the ethics of nuclear weapons (Hardin, Goodin,
Mearsheimer, & Dworkin, 1985; Nye, 1986), the constructivist wave intensified the consideration of norms, status, and identity in the non/pursuit
of weapons of mass destruction (Husbands, 1982; Tannenwald, 2005, 2007).
From this perspective, the significance of the NPT regime does not center
on its ability to reduce transaction costs or other rationalistic considerations.

Why do States Pursue Nuclear Weapons (or Not)

5

Rather, international institutions and norms are sociological phenomena
reflecting and imprinting the collective identities of member states, changing
actors’ beliefs and identities, and altering the very definition of interests
(Finnemore & Sikkink, 1998; Johnston, 2001; Klotz & Lynch, 2007; March &
Olsen, 1998). Institutions “constitute and construct the social world” (Barnett
& Finnemore, 1999, p. 700). The NPT regime, in this view, stems from the evolution of antinuclear weapons norms embedded in the centerpiece treaty. The
regime socialized nuclear and nonnuclear bureaucracies, created new expectations and habits, and transformed states’ beliefs about the ethical status of
nuclear weapons, thereby leading to near-universal compliance. Overall, it
stands as a constellation of entities that restrict freedom of action on nuclear
matters and has contributed to the emergence of a taboo defining nuclear
weapons as unconventional, abhorrent, and unacceptable (Schelling, 2000).
Yet, evidence for the norm against acquisition of nuclear weapons is far
more questionable than a norm against their use (Solingen, 2007; Walker,
2010). Weapons development has spanned more than half a century in
the aftermath of the Manhattan Project, from the first Soviet nuclear test
in 1949 to the most recent North Korean test in 2013 ; the consideration
of nuclear weapons by Sweden, Norway, Yugoslavia, Switzerland, and
others also questions the existence of a taboo. There are too many anomalies
throughout the life span of the NPT, with another 15 states seeking to
acquire weapons-related capabilities through the 1990s and several cases
of noncompliance with safeguards in the early 2000s in Iran, Libya, South
Korea, and Egypt. Very mild international responses to India and Pakistan’s
1998 tests further undermine the argument of a prohibition taboo, as do more
recent discussions of new nuclear claimants such as Saudi Arabia and others.
Nuclear weapons have not been “unthinkable” even in Japan, a “crucial” case for antinuclear norms, given the experiences of Hiroshima and
Nagasaki. Japan’s pacifist movement sensitized its leaders to domestic
opposition to nuclear weapons, but this was only one strand in Japan’s
public opinion. The very conduct of several government studies on Japan’s
nuclear options suggests that nuclear weapons’ acquisition—although
unlikely—was less than a taboo (Okimoto, 1978). Public opinion polls suggest that the “nuclear allergy” was much stronger subsequently than during
the first two decades of the postwar era, when historic nuclear decisions
were under consideration (Solingen, 2010). Japan delayed ratification of NPT
by nearly 7 years, which stood in contrast with its sustained support for UN
multilateralism in the postwar era. While domestic institutional restraints
such as the Atomic Energy Law and the Three Nonnuclear Principles had
significant force, there was also continuous contestation over interpretations
of Article IX of the Constitution (renouncing the right of belligerency without
referring to nuclear weapons), which may explain why the Principles never

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

became law (Chai, 1997). Even the reliance on the US nuclear umbrella was
not precisely a policy suggestive of nuclear abstinence. Compromises over
US introduction of nuclear weapons into Japan were also an expression
of what opponents of nuclear weapons considered akin to “embedded
nuclearization.” As Mochizuki (2006) argued, “Japan’s pacifism has always
been pragmatic.”
All these cases, and continued expectations of nuclear dominoes in the
Middle East and Asia—responsive to nuclearized Iranian or North Korean
threats—continue to question the existence of a taboo against acquisition.
United Nations Secretary-General Kofi Annan suggested in 2006 that many
states were revisiting their logic on the issue of nuclear weapons (Broad &
Sanger, 2006). As with the other theories, conceptual, methodological, and
empirical problems plague the normative/sociological account.
DOMESTIC MODELS OF POLITICAL SURVIVAL (MPS)
The three preceding theoretical frameworks share a fundamental inattention to an important omitted variable: domestic political drivers. In a
study of Taiwan, Bueno de Mesquita, Morrow, and Wu (1993) argued that
nuclear behavior is necessarily linked to a supportive domestic coalition.
This was a progressive move away from both underdetermining systemic
balance of power considerations and a reductionist focus on treaties, taboos,
and arguments focused on individual leaders as single-handedly driving
outcomes. Yet, coalitions come in many forms; the microfoundations of
why some coalitions might support the acquisition of nuclear weapons
(whereas others might not) remained undertheorized. Focusing on the
domestic distributional consequences of integration in the global political
economy as a point of departure, Solingen (1994a, 1994b) identified two
ideal-typical coalitions, advancing competing models of political survival
(MPS) in power. These models entailed not simply different orientations to
the global political economy and associated economic, political, and security
institutions; they also had different implications for nuclear choices in the
aftermath of the 1970 inception of the NPT.
While nuclear proliferation and political economy had been highly segregated fields of inquiry, “The Political Economy of Nuclear Restraint,”
published in International Security in 1994, foregrounded the linkages
between the two along the following lines: Internationalizing coalitions
advocating economic growth through integration in the global economy
had incentives to avoid the domestic and international, political and economic (including opportunity) costs of embarking on nuclear weapons
programs. They were more receptive to renouncing nuclear weapons for
several synergistic reasons: to enhance their appeal to foreign investors,

Why do States Pursue Nuclear Weapons (or Not)

7

signaling a commitment to economic growth and stability; to reassure
neighbors and boost regional cooperation, stability, and attractiveness; to
secure access to international markets for exports, capital, technology, and
raw materials; to avoid incurring reputational losses at home and abroad
for uncertain nuclear gains; and to avoid alienating domestic agents of
internationalization that might be adversely affected by nuclear weapons
development. Such weapons, in other words, would burden efforts to
enhance exports, economic competitiveness, macroeconomic and political
stability, and global access, all objectives of internationalizing models, and
would strengthen adversarial state bureaucracies and industrial complexes
opposed to economic openness.
Inward-looking coalitions had greater tolerance—and sometimes strong
incentives—to develop nuclear weapons. Nuclearization entailed fewer
costs for political platforms rooted in mistrust for international markets, investment, technology, and institutions. Backed by protected and
uncompetitive national industries, sprawling state enterprises and ancillary military–industrial and nuclear complexes, foes of internationalizing
models benefited from import substitution, nationalism, and claims of
self-sufficiency. They thus had greater incentives to exploit nuclear weapons
as tools in inward-looking platforms of political competition and survival;
often relied on extreme language to compel and threaten regional adversaries; misled or violated international nonnuclear commitments; and were
more promiscuous regarding state-directed or state-endorsed dissemination
of sensitive nuclear technologies as sources of financing inward-looking
models.
Thus, whereas nuclear weapons programs may have been assets in the
arsenal to build inward-looking regime legitimacy, they were drawbacks for
outward-oriented models.
These hypothesized patterns of nuclear behavior find support from
systematic observations in the Middle East, East Asia, and beyond across
different regional security contexts, diverse associations with hegemonic
powers, and over successive leaderships within the same state. Heavy
regional concentration of internationalizing models in East Asia since the
1970s reinforced each state’s incentives to avoid nuclearization. Conversely,
heavy regional concentration of nationalist, protectionist, and militarized
models throughout the Middle East exacerbated mutual incentives to
develop nuclear weapons. Considering the relevant universe of cases
where nuclear weapons were entertained or launched over the last four
decades, not one endorsed denuclearization––fully and effectively––under
inward-looking models. Only internationalizing coalitions undertook
effective commitments to eschew nuclear weapons, from Egypt (under
Sadat) to South Africa, Brazil, Argentina, Japan, Taiwan, South Korea,

8

EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

Spain, and Libya in 2003. Most defiant nuclear courses were associated with
inward-looking models, from Argentina under Perón (Liberación o Muerte) to
North Korea (juche), India (swadeshi), and equivalents in Pakistan, Nasser’s
Egypt, Iraq, Iran, and Libya pre-2003. The pace and timing of renunciation
was nested in broader shifts toward internationalization in economics
and security. Where internationalizing models were stronger politically,
departures from nuclear claims were sustained even where the security
context remained challenging, as in Japan, South Korea, and Taiwan. Weaker
internationalizing coalitions in Iran, Pakistan, and Argentina and Brazil until
the 1990s were more politically constrained in curbing nuclear programs. A
model’s relative regional incidence influenced nuclear decisions more than a
neighbor’s nuclearization per se.
These MPS help explain why different actors within the same state diverge
in their approaches and preferences regarding nuclear policy; why a state’s
nuclear policies may vary over time as a function of the relative power of
particular domestic forces; why different states vary in their commitments
to increase information, transparency, and compliance with international
commitments; why security dilemmas are sometimes seen as more (or
less) obdurate; why some states rank alliances higher than self-reliance
but not others; when and how hegemonic coercion and inducements are
effective and when they play a secondary or marginal role; why nuclear
weapons’ programs surfaced where there was arguably little need for them
(the Southern Cone or South Africa among others); and why such programs
were obviated where one might have expected them (Vietnam, Singapore,
Jordan, and many others).
The omission of this significant independent variable in first-generation
studies may have led to an overestimation of other causal variables (balance
of power, institutions, norms) and to potential spurious effects. Its inclusion
may improve our understanding of the actual effects of security dilemmas,
international norms, and institutions. This is different from arguing that MPS
are the only relevant variable; only that MPS enable a better understanding
of the relative impact of other variables on nuclear choices. Indeed, several
empirical studies have provided support for a MPS framework (Liberman,
2001; Solingen, 2004, 2007). Potter and Mukhatzhanova (2008, 2010) endorsed
its caution in overestimating the effects of any single causal variable and
its solid grounding in comparative field research and social science theory.
They found it particularly persuasive in accounting for much of the variation over time across and within states. For instance, internationalizing coalitions relinquished the nuclear option even in the absence of alliances (Egypt,
South Africa, Argentina, Brazil). The centrality of MPS is especially notable
since the evidentiary dice (archives, statements, etc.) is loaded against ulterior domestic political justifications. Leaders have incentives to cast decisions

Why do States Pursue Nuclear Weapons (or Not)

9

favoring or rejecting nuclear weapons as “reasons of state” invoking national
security, international institutional incentives, or normative considerations.
Hence, whereas nuclear behavior provides neorealism with “most likely”
conditions for supporting its tenets, it offers “least likely” conditions for corroborating a MPS argument. Consequently, empirical support for findings
along these lines gains particular significance in this unfriendly terrain.
MPS may not capture all the correlates of nuclear preferences and are, after
all, only ideal types, conceptual constructs rather than historical or “true”
realities. As such, they need not fit every case or indeed any particular case
completely (Eckstein, 1975), but rather provide a heuristic, a helpful shortcut, and a fruitful comparative framework capable of reducing a complex
reality down to some fundamentals. Propositions derived from a MPS framework remain bounded in three ways: with respect to conditions of necessity
and sufficiency in developing nuclear weapons; the incidence of compatible
models in the region; and temporal sequences in the acquisition of nuclear
weapons. Eliminating existing weapons may be more costly politically than
eradicating precursor programs, as stipulated by prospect theory, and the
incentives emanating from the global political economy may operate more
forcefully both at earlier stages in the inception of internationalizing models
and earlier stages in the consideration of nuclear weapons. These hypotheses
remain subject to further investigation.
RECENT RESEARCH DEVELOPMENTS
There has been a significant shift across the methodological range toward
theorizing and testing the role of domestic political drivers to a much greater
extent than was the case two decades ago. The international relations theory
toolkit for studying nuclear decision-making is far more sophisticated theoretically and more diverse methodologically. However, it still suffers from
weak efforts to rely on complementary methods, to explore linkages across
perspectives, and to envisage scope conditions for the operation of different
variables across time and space. The absence of a more analytically eclectic
approach (Sil & Katzenstein, 2010) has hindered the field as a whole, with
works too often speaking past rather than building on one another.
In particular, the last decade has witnessed the newfound application of
quantitative methods to gauge the nuclear motivations of states. Jo and
Gartzke (2007, p. 186) downplay the general role of domestic political
factors––regime type plays no role in the initial decision to nuclearize. Their
study is in many ways an affirmation of the neorealist argument: states’
willingness to seek nuclear weapons is linked to “external concerns,” and
especially to “countervail conventional disadvantage.” Singh and Way
(2004) not only similarly highlighted the external threat environment, but

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

also found support for the propositions that “the process of economic
liberalization is associated with a reduced likelihood of exploring nuclear
weapons;” that “economic openness has a statistically significant negative
effect across all three levels of proliferation” (i.e., exploring, pursuing, or
acquiring them); and that “economic liberalization dampened the risk” of
states deciding “to explore seriously the nuclear option” (pp. 876, 878). This
study also recognizes that the connection might have been even stronger,
had cases of states that abandoned nuclear programs been included. Also
excluded were prospective efforts to enhance economic openness and attract
foreign investment, which are the crucial drivers in MPS arguments. There is
no one-to-one correspondence between incentives and efforts to open up the
economy at time T and measures of trade openness at T+1. Fuhrmann and
Li (2008) found that economic liberalization had a positive and statistically
significant effect on nuclear-weapon-free zone treaty ratification as well.
Yet, the process by which those treaties emerge suggests the possibility of
selection effects.
Overall, the quantitative turn has done little to settle debates regarding
state motivations to acquire or renounce nuclear weapons. Given their
disparate findings, the diversity of datasets, coding rules, and statistical methods has only served to muddle the waters; furthermore, the
operationalization of variables failed to capture the nuance of some theories,
undermining the robustness of their conclusions (Montgomery & Sagan,
2009; Sagan, 2011). Many studies, for instance, rely on the Composite Index
of National Capabilities in order to measure state power. Yet, such an
operationalization obscures the subjectivity inherent in notions of power,
overlooking the role of different domestic actors in shaping the definition
and perception of threats. The notion of institutional effects is oftentimes
reduced to NPT membership, severely underrepresenting the depth of the
nonproliferation regime. The negative correlation between existing levels
of trade openness and nonproliferation in some studies is curious, but
quantitative studies are ill-suited to make causal claims about the nature of
ruling coalitions, their expected utilities, the crucial role played by regional
coalitional homogeneity/heterogeneity, and the implications of all these for
the pursuit or renunciation of nuclear weapons.
Several recent works have infused social psychology into the study of
proliferation, following the broader constructivist turn in international
relations theory. Long and Grillot’s (2000) overview of South African and
Ukrainian denuclearization argued that causal beliefs about their respective
Western identities played “a significant role both in preference formation
and strategic choice regarding nuclear policymaking” (p. 36). However, the
conceptualization of these causal beliefs appears overly deterministic and

Why do States Pursue Nuclear Weapons (or Not)

11

inflexible, hardly allowing for the possibility of domestic dissension regarding those identities. South Africa’s Western identity was firmly in place
by the 1940s, they argue, with only slight fluctuations subsequently, while
Ukranian leaders simply began asserting Ukraine’s status as a European
state after independence. Hymans (2006) linked the individual identity of
state leaders—“oppositional nationalists” —with the drive toward nuclear
weapons’ ambitions. Yet, individual psychology as a causal factor presents
significant methodological challenges, including accurate assessment of
the leaders’ presumed profiles. For instance, Japan’s nonnuclear status is
often—wrongly—traced to Premier Sato’s putative antinuclear weapons
commitments (he received the Nobel Prize on that account). But, declassified
records suggest otherwise: Sato conveyed to US Ambassador Reischauer
a personal preference for a nuclear Japan in 1964, oversaw a confidential
inquiry into possible distinctions between offensive and defensive nuclear
weapons in 1967 (the latter allowed by Japan’s constitution according to
some readings), and declared in a 1969 meeting with business leaders that a
defense system was incomplete “if we cannot possess nuclear weapons in
the era of nuclear weapons” (Solingen, 2007, p. 73).
Further exploration of the Japanese case demonstrates the empirical fallacies of attributing nuclear policy to individual psychology. The confluence
of major systemic triggers (North Korea’s repeated nuclear and missile tests,
the rise of China, conflict over the Senkaku/Diaoyu and Takeshima/Dokdo
islands) and strong conservative leaders at Japan’s helm have not yielded
the shifts expected by personality—or neorealist—variables (Mearsheimer,
1981). The succession of a large number of premiers over decades—with a
wide range of personalities and psychological identities—has yielded the
same outcome thus far. This includes the “most-likely” (ideational) cases
of Premiers Fukuda Yasuo, Aso Taro and Abe Shinzo, the latter an ardent
conservative nationalist at heart who learned about Japanese strategic
options at his grandfather’s (Kishi’s) knee. Yet, he did not move Japan
beyond the nonnuclear principles in his first term or even his second, after
North Korea tested nuclear weapons three times, once under his watch.
Abe reaffirmed Japan’s nonnuclear status, aware of the economic, political,
regional, and global requirements without which Japan’s survival in the
twenty-first century global political economy could not be guaranteed.
Such deficiencies of personality-based approaches led Rublee (2009) to link
nuclear forbearance to the international social environment, highlighting
mechanisms of persuasion, social conformity, and identification. Yet, despite
her acknowledgment that “some segments of a state may be more susceptible than others” (p. 5), her treatment of domestic politics remains imprecise.
The discussion of social costs can also obscure the connection of nuclear
issues to other domestic concerns, leading to seemingly inconsistent policies

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

that are more difficult to reconcile with identity-based factors. For instance,
despite Sato’s chronicled private inclinations toward nuclear weapons’
acquisition, his foremost political purpose was Okinawa’s reversion to
Japan––a goal he was prepared to advance even if it meant accepting the
formal adoption of the nonnuclear principles in exchange for the Diet’s
approval of his Okinawa agreement. As available historical data suggest,
political survival models and “audience costs” considerations appear to
have neutralized other proclivities that Kishi, Yoshida, Sato, Nakasone,
Aso, or others have had and expressed publicly. Ultimately, the ideational
qualitative studies vary in the extent to which they contend seriously with
competing hypotheses and are amenable to systematic testing.
THE AGENDA AHEAD
The classic perspectives remain very much part of the menu in the study
of nuclear behavior. However, a future agenda should move beyond
indeterminacy, tautologies, or posthocism. Studies along neorealist lines
must cast their arguments precisely and in falsifiable terms; grapple with
more precise notions of power and vulnerability; further stipulate the
impact of alliances and hegemonic guarantees; and specify threshold
conditions for nuclear breakout. Given their systemic assumptions, they
must explain variation in nuclear behavior independently of domestic or
other auxiliary considerations extraneous to structural (relative) power.
Studies advancing neoliberal institutionalist perspectives must expand the
empirical base for stipulating causal linkages between regime membership
and nuclear decisions; address the problem of selection effects through
counterfactual analysis of decisions in a hypothetical environment free of
NPT commitments; and reconcile the presumption of Pareto-optimality
with the reality of power hierarchies in the NPT (Wan, 2014a). Constructivist work must distinguish across nuclear norms (acquisition, use, etc.);
explain the resilience of advocacy for nuclear weapons in nuclear weapons
states and some nuclear aspirants; improve our understanding of selective
socialization into antinuclear weapons norms; explain clustered regional
behavior toward or away from nuclearization under the shadow of the
same international norm (or, why has the norm diffused selectively); and
complement normative accounts of nuclear weapons’ acquisition or rejection
with a theory of domestic politics (or, what explains domestic receptivity
to some norms but not others) that may explain barriers to norm diffusion.
Political survival models must improve classification of coalitions along the
internationalizing/inward-looking spectrum; estimate thresholds beyond
which coalitional shifts might overturn a trajectory toward or away from
nuclear weapons (in other words, when can path-dependence dominate

Why do States Pursue Nuclear Weapons (or Not)

13

coalitional tendencies); and consider the impact of world-time––and an
evolving global economy––on the character of coalitions.
Analysis of nuclear behavior that is attentive to complexity—interaction
among variables—and to historical context can enhance both historical accuracy and predictive capabilities. As Philip Tetlock’s (2005) masterful treatise
on expert political judgment and prediction suggests, parsimony can be the
enemy of accuracy, a substantial liability in real-world forecasting. Quantitative work should be more attentive to the inclusion of relevant cases only
(Cape Verde does not add much validity to a database on this topic); improve
the fit between variables and conceptual arguments; harmonize databases;
and integrate more recent and sophisticated arguments from the overarching international relations toolkit. Qualitative studies should improve the
criteria for case selection, seeking crucial cases and least likely conditions
that force the empirical analysis to overcome difficult conditions. Cases that
feature a reversal of course in either direction seem especially fruitful analytically, the various periods of fluctuation enhancing the number of observations and the opportunity to gauge variation over time. Nuclear outcomes
may be conceptualized not as finite and final but as malleable and operating
on a continuum.
One may find an approach reasonably persuasive in explaining the past, but
it does not necessarily follow that it will also apply in the future. Nonetheless, causal theories must be able to lay out a priori what kind of evidence
would question or corroborate their expectations. They must avoid suggesting many outcomes that would all be consistent with one particular value
of their key variable, to elude the problem of multifinality. Clarity is a sine
qua non for avoiding circularity and ex post facto rationalizations (such as
“state x went nuclear because of acute insecurity,” whereby a nuclear test is
used to signal a posteriori, retroactively, that an acute threshold of insecurity
has been crossed). Arguments must be cast in falsifiable terms a priori, with
more clearly defined and testable propositions. Sensitivity to these and other
conceptual and methodological issues described above can lead to analytical progress and offer better policy insight on the processes and mechanisms
that drive the nuclear behaviors of states.
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FURTHER READING
Potter, W. C., & Mukhatzhanova, G. (Eds.) (2010). Forecasting nuclear proliferation
in the 21st century. Stanford, CA: Stanford Security Studies/Stanford University
Press.
Sagan, S. D. (2011). The causes of nuclear weapons proliferation. Annual Review of
Political Science, 14(1), 225–244.
Solingen, E. (2007). Nuclear logics: Contrasting paths in East Asia and the Middle East.
Princeton, NJ: Princeton University Press.

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WILFRED WAN SHORT BIOGRAPHY
Wilfred Wan is a Japan Society for the Promotion of Science-United
Nations University Postdoctoral Fellow working with the UNU Centre
for Policy Research in Tokyo. He was a 2013–2014 Social Science Research
Council–JSPS Postdoctoral Fellow at Hitotsubashi University. He spent 2
years as a predoctoral fellow with an International Security Program and
Project on Managing the Atom joint appointment at the Belfer Center for
Science and International Affairs (Harvard Kennedy School), including one
as a Stanton Nuclear Security Fellow. He is also a former Institute on Global
Conflict and Cooperation Dissertation Fellow. He has co-authored a chapter
in Sanctions, Statecraft, and Nuclear Proliferation (Cambridge University
Press).
ETEL SOLINGEN SHORT BIOGRAPHY
Etel Solingen is the Thomas T. and Elizabeth C. Tierney Chair in Peace Studies at the University of California Irvine and former UCI Chancellor’s Professor and President of the International Studies Association. Her book Nuclear
Logics: Contrasting Paths in East Asia and the Middle East (Princeton U.P.)
received the APSA’s 2008 Woodrow Wilson Foundation Award for the best
book in all fields and the 2008 APSA’s Robert Jervis and Paul Schroeder
Award for the best book on International History and Politics.
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Why do States Pursue Nuclear
Weapons (or Not)
WILFRED WAN and ETEL SOLINGEN

Abstract
This essay traces the evolution of the literature on the rationale behind states’ pursuit of nuclear weapons, from classical neorealist explanations focusing on relative
power to neoliberal institutionalist ones underlining the deterrent power of institutions and constructivist work on the impact of norms, status, and identities. We call
attention to their contributions as well as their conceptual and empirical deficiencies
and introduce an approach that links both nuclear ambition and nuclear restraint
to models of domestic political survival. The inclusion of this previously overlooked
independent variable harnesses the utility of extant approaches, allowing more effective weighing of the impact of other causal variables, while accounting for variation
over time, across and within states. We take stock of more recent work employing
quantitative and qualitative approaches and identify an agenda for advancing causal
theories explaining why some states pursue nuclear weapons whereas others do not.

INTRODUCTION
What are the driving forces behind state decisions to pursue nuclear
weapons, to reverse course in their quest, or to reject them altogether?
Since the onset of the nuclear age, a breadth of scholarship has detailed the
incentives and disincentives that account for nuclear behavior, including
security, status/prestige, cost, technical difficulties, and domestic and international opposition. Single-country historical accounts and policy-oriented
studies dominated the first phase of this literature. This tendency placed
some limits on generalizability, given the modest number of cases and data
restrictions during the Cold War. Theoretical analysis was relatively limited
and circumscribed to balance of power theory, known also as neorealism. The
1990s witnessed efforts to broaden the theoretical repertoire and transcend
monocausal explanations, challenging the dominant neorealist paradigm
(Lavoy, 1993; Ogilvie-White, 1996; Sagan, 1996; Solingen, 1994a, 1994b). This

Emerging Trends in the Social and Behavioral Sciences. Edited by Robert Scott and Stephen Kosslyn.
© 2015 John Wiley & Sons, Inc. ISBN 978-1-118-90077-2.

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trend, however, also led to contestation regarding the main causal drivers
for acquiring nuclear weapons or abstaining from doing so.
We begin by exploring three main approaches: neorealism, neoliberal institutionalism, and constructivism. We acknowledge the important insights
each provides but also raise some conceptual difficulties; the empirical
record further challenges their validity and generalizability. The study of
proliferation pathways requires a degree of analytical flexibility not afforded
by these extant theories in isolation. A fuller understanding of nuclear
decisions requires a framework able to estimate whether, when, and how
relative power, international institutions, and norms weigh on different
cases. We introduce an approach pivoted on domestic political survival
models capable of endogenizing those variables, a framework applicable to
the universe of cases (Solingen, 1994a, 1994b, 2007). Our final section raises
challenges for future research.
THEORETICAL EVOLUTION OF THE FIELD
NEOREALISM
Neorealist theory provided the conventional explanation for nuclear
behavior: the absence of an ultimate authority above the sovereign state
perpetuates a purely competitive international structure, leading states to
the “individualistic pursuit of security,” “self-help,” and balance of power
(Dunn, 1982; Jervis, 1982; Rosecrance, 1964; Waltz, 1981). The pursuit of
nuclear weapons, accordingly, is an imperative of state survival in an
anarchic world. But, why have so many states abdicated that canon? External insecurity has proven an insufficient condition for nuclear weapons’
acquisition (Betts, 2003). Egypt, South Korea, Jordan, Taiwan, and Japan,
all ultimately eschewed nuclear weapons, even as their rivals acquired or
developed them. Some neorealist scholars invoke the role of alliances in
explaining anomalies (Paul, 2000). Yet, the evidence for that is similarly
mixed. The absence of alliances and hegemonic guarantees did not prevent
states from reversing nuclear ambitions, as with Egypt, Libya, South Africa,
Argentina, and Brazil. Conversely, coercive action by the United States and
the Soviet Union did not stop North Korea, India, Pakistan, or Israel from
weapons’ acquisition. The putative structural trap may be less confining
than stipulated by neorealism: states opt for different solutions—nuclear
and nonnuclear—to comparable security predicaments.
Such inconsistencies in the empirical record are compounded by fundamental conceptual difficulties, including elastic and subjective definitions
of vulnerability and power (Haas, 1953). A focus on “threats” (Walt, 1987)
draws attention away from systemic consideration, squarely on which

Why do States Pursue Nuclear Weapons (or Not)

3

domestic actors define what constitutes a threat. Crucially, neorealist theory
is underdetermining, allowing for multiple possible outcomes: state survival might be secured by a wide range of behavior. Nuclear weapons may
enhance or undermine security. The thresholds explaining nuclearization
are unclear at best: power differentials lead to open-ended operational
implications ranging between abstention and acquisition.
These deficiencies raise a fundamental analytical and methodological consideration.
High national security is the arena where neorealism should perform
best, its home court, easy grounds for testing theories of balance of power
and state security under anarchy. Nuclear weapons are at the heart, the
inner sanctum of states’ security dilemmas. This is the theory’s most auspicious domain for corroborating its tenets, loading the dice in its favor.
Further, leaders, politicians, and bureaucrats are more likely to portray
decisions for or against nuclear weapons as dictated by “state survival”
rather than domestic political expediency or other factors. The evidentiary
record—public and private—thus tilts the analysis toward an already
privileged theoretical driver. All these considerations magnify the weight of
empirical anomalies.
A theory that cannot be easily confirmed at high levels of confidence, even
under the best circumstances, compels serious rethinking. Nuclear outcomes
are clearly not the sole perfunctory reflection of international power structure.
NEOLIBERAL INSTITUTIONALISM
The neoliberal institutionalist school of thought emerged to challenge
neorealist assumptions regarding cooperation, questioning the rigidity and
severity of the self-help world, and offering institutions as the means to
reduce conflict (Jervis, 1999). Institutions provide an attractive alternative
to the unilateral pursuit of security: they lower transaction costs, enhance
information about preferences and behaviors, monitor compliance, detect
defections, and foster repeated and continuous interactions between states
(Axelrod & Keohane, 1985; Keohane, 1984; Lipson, 1984; North, 1981). Their
presence constrains state behavior, altering strategies and beliefs over outcomes. Significantly, the nuclear arena boasts one of the most prominent and
long-lasting international institutions. The Treaty on the Nonproliferation
of Nuclear Weapons (NPT) has become the center of an encompassing
regime that includes organizations (e.g., the International Atomic Energy
Agency [IAEA]), negotiating forums (Conference on Disarmament), consortiums (Nuclear Suppliers Group), and nested treaties (Comprehensive Test
Ban Treaty, Nuclear-Weapon-Free Zones) (Wan, 2014b). The International

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Atomic Energy Agency safeguards agreements in place under the NPT aim
to prevent the diversion of materials from peaceful nuclear activities to
weapons programs, while the 1997 optional Additional Protocol expanded
the range of information submitted by the states and granted the IAEA
complementary access for verification. As Nye argued (1988, p. 336), “That
most states adhere to a regime in which they foreswear the right to use the
ultimate form of self-help in technological terms is quite an extraordinary
situation.”
Placed under closer scrutiny, however, a narrative that links the NPT
regime to the nuclear decisions of states––as in the work of Walsh
(2005)––encounters myriad difficulties. While it is reasonable to presume that states join international institutions with an eye on absolute
(rather than relative) gains, the extent to which that presumption has held in
this arena is questionable and fundamentally understudied empirically. The
durability of the NPT regime masks long-standing discord regarding the
central bargain. There is widespread belief among nonnuclear weapon states
that the NPT does not represent “collective interests, but rather [serves] as
an instrument utilized by the major powers … to constrain and discipline
other states” (Miller, 2012, pp. 8–9). Further, challenges posed by nonstate
actors, by noncompliance with safeguards, and by enforcement issues
undermine the image that the regime fulfills the promise of international
institutions (Braun & Chyba, 2004; Goldschmidt, 2009). Beyond all that, we
do not yet have a systematic empirical foundation that would allow us to
ascertain whether or not the NPT regime has played a central role in the
nuclear behaviors of states. Selection effects, the reasons that led states to
join the treaty––domestic interests, hegemonic coercion, and others––may
in fact explain subsequent compliance (and the rejection of nuclearization)
better than the NPT itself. As Guzman (2008, p. 80) suggests, “for many
[parties] … one would expect compliance even in the absence of a treaty.”
As with neorealism, neoliberal institutionalism encounters very significant
difficulties when considering causal processes, including the sequence,
effect, and mechanisms connecting regime membership to nuclear weapons’
renunciation.
CONSTRUCTIVISM
While earlier work explored the ethics of nuclear weapons (Hardin, Goodin,
Mearsheimer, & Dworkin, 1985; Nye, 1986), the constructivist wave intensified the consideration of norms, status, and identity in the non/pursuit
of weapons of mass destruction (Husbands, 1982; Tannenwald, 2005, 2007).
From this perspective, the significance of the NPT regime does not center
on its ability to reduce transaction costs or other rationalistic considerations.

Why do States Pursue Nuclear Weapons (or Not)

5

Rather, international institutions and norms are sociological phenomena
reflecting and imprinting the collective identities of member states, changing
actors’ beliefs and identities, and altering the very definition of interests
(Finnemore & Sikkink, 1998; Johnston, 2001; Klotz & Lynch, 2007; March &
Olsen, 1998). Institutions “constitute and construct the social world” (Barnett
& Finnemore, 1999, p. 700). The NPT regime, in this view, stems from the evolution of antinuclear weapons norms embedded in the centerpiece treaty. The
regime socialized nuclear and nonnuclear bureaucracies, created new expectations and habits, and transformed states’ beliefs about the ethical status of
nuclear weapons, thereby leading to near-universal compliance. Overall, it
stands as a constellation of entities that restrict freedom of action on nuclear
matters and has contributed to the emergence of a taboo defining nuclear
weapons as unconventional, abhorrent, and unacceptable (Schelling, 2000).
Yet, evidence for the norm against acquisition of nuclear weapons is far
more questionable than a norm against their use (Solingen, 2007; Walker,
2010). Weapons development has spanned more than half a century in
the aftermath of the Manhattan Project, from the first Soviet nuclear test
in 1949 to the most recent North Korean test in 2013 ; the consideration
of nuclear weapons by Sweden, Norway, Yugoslavia, Switzerland, and
others also questions the existence of a taboo. There are too many anomalies
throughout the life span of the NPT, with another 15 states seeking to
acquire weapons-related capabilities through the 1990s and several cases
of noncompliance with safeguards in the early 2000s in Iran, Libya, South
Korea, and Egypt. Very mild international responses to India and Pakistan’s
1998 tests further undermine the argument of a prohibition taboo, as do more
recent discussions of new nuclear claimants such as Saudi Arabia and others.
Nuclear weapons have not been “unthinkable” even in Japan, a “crucial” case for antinuclear norms, given the experiences of Hiroshima and
Nagasaki. Japan’s pacifist movement sensitized its leaders to domestic
opposition to nuclear weapons, but this was only one strand in Japan’s
public opinion. The very conduct of several government studies on Japan’s
nuclear options suggests that nuclear weapons’ acquisition—although
unlikely—was less than a taboo (Okimoto, 1978). Public opinion polls suggest that the “nuclear allergy” was much stronger subsequently than during
the first two decades of the postwar era, when historic nuclear decisions
were under consideration (Solingen, 2010). Japan delayed ratification of NPT
by nearly 7 years, which stood in contrast with its sustained support for UN
multilateralism in the postwar era. While domestic institutional restraints
such as the Atomic Energy Law and the Three Nonnuclear Principles had
significant force, there was also continuous contestation over interpretations
of Article IX of the Constitution (renouncing the right of belligerency without
referring to nuclear weapons), which may explain why the Principles never

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became law (Chai, 1997). Even the reliance on the US nuclear umbrella was
not precisely a policy suggestive of nuclear abstinence. Compromises over
US introduction of nuclear weapons into Japan were also an expression
of what opponents of nuclear weapons considered akin to “embedded
nuclearization.” As Mochizuki (2006) argued, “Japan’s pacifism has always
been pragmatic.”
All these cases, and continued expectations of nuclear dominoes in the
Middle East and Asia—responsive to nuclearized Iranian or North Korean
threats—continue to question the existence of a taboo against acquisition.
United Nations Secretary-General Kofi Annan suggested in 2006 that many
states were revisiting their logic on the issue of nuclear weapons (Broad &
Sanger, 2006). As with the other theories, conceptual, methodological, and
empirical problems plague the normative/sociological account.
DOMESTIC MODELS OF POLITICAL SURVIVAL (MPS)
The three preceding theoretical frameworks share a fundamental inattention to an important omitted variable: domestic political drivers. In a
study of Taiwan, Bueno de Mesquita, Morrow, and Wu (1993) argued that
nuclear behavior is necessarily linked to a supportive domestic coalition.
This was a progressive move away from both underdetermining systemic
balance of power considerations and a reductionist focus on treaties, taboos,
and arguments focused on individual leaders as single-handedly driving
outcomes. Yet, coalitions come in many forms; the microfoundations of
why some coalitions might support the acquisition of nuclear weapons
(whereas others might not) remained undertheorized. Focusing on the
domestic distributional consequences of integration in the global political
economy as a point of departure, Solingen (1994a, 1994b) identified two
ideal-typical coalitions, advancing competing models of political survival
(MPS) in power. These models entailed not simply different orientations to
the global political economy and associated economic, political, and security
institutions; they also had different implications for nuclear choices in the
aftermath of the 1970 inception of the NPT.
While nuclear proliferation and political economy had been highly segregated fields of inquiry, “The Political Economy of Nuclear Restraint,”
published in International Security in 1994, foregrounded the linkages
between the two along the following lines: Internationalizing coalitions
advocating economic growth through integration in the global economy
had incentives to avoid the domestic and international, political and economic (including opportunity) costs of embarking on nuclear weapons
programs. They were more receptive to renouncing nuclear weapons for
several synergistic reasons: to enhance their appeal to foreign investors,

Why do States Pursue Nuclear Weapons (or Not)

7

signaling a commitment to economic growth and stability; to reassure
neighbors and boost regional cooperation, stability, and attractiveness; to
secure access to international markets for exports, capital, technology, and
raw materials; to avoid incurring reputational losses at home and abroad
for uncertain nuclear gains; and to avoid alienating domestic agents of
internationalization that might be adversely affected by nuclear weapons
development. Such weapons, in other words, would burden efforts to
enhance exports, economic competitiveness, macroeconomic and political
stability, and global access, all objectives of internationalizing models, and
would strengthen adversarial state bureaucracies and industrial complexes
opposed to economic openness.
Inward-looking coalitions had greater tolerance—and sometimes strong
incentives—to develop nuclear weapons. Nuclearization entailed fewer
costs for political platforms rooted in mistrust for international markets, investment, technology, and institutions. Backed by protected and
uncompetitive national industries, sprawling state enterprises and ancillary military–industrial and nuclear complexes, foes of internationalizing
models benefited from import substitution, nationalism, and claims of
self-sufficiency. They thus had greater incentives to exploit nuclear weapons
as tools in inward-looking platforms of political competition and survival;
often relied on extreme language to compel and threaten regional adversaries; misled or violated international nonnuclear commitments; and were
more promiscuous regarding state-directed or state-endorsed dissemination
of sensitive nuclear technologies as sources of financing inward-looking
models.
Thus, whereas nuclear weapons programs may have been assets in the
arsenal to build inward-looking regime legitimacy, they were drawbacks for
outward-oriented models.
These hypothesized patterns of nuclear behavior find support from
systematic observations in the Middle East, East Asia, and beyond across
different regional security contexts, diverse associations with hegemonic
powers, and over successive leaderships within the same state. Heavy
regional concentration of internationalizing models in East Asia since the
1970s reinforced each state’s incentives to avoid nuclearization. Conversely,
heavy regional concentration of nationalist, protectionist, and militarized
models throughout the Middle East exacerbated mutual incentives to
develop nuclear weapons. Considering the relevant universe of cases
where nuclear weapons were entertained or launched over the last four
decades, not one endorsed denuclearization––fully and effectively––under
inward-looking models. Only internationalizing coalitions undertook
effective commitments to eschew nuclear weapons, from Egypt (under
Sadat) to South Africa, Brazil, Argentina, Japan, Taiwan, South Korea,

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Spain, and Libya in 2003. Most defiant nuclear courses were associated with
inward-looking models, from Argentina under Perón (Liberación o Muerte) to
North Korea (juche), India (swadeshi), and equivalents in Pakistan, Nasser’s
Egypt, Iraq, Iran, and Libya pre-2003. The pace and timing of renunciation
was nested in broader shifts toward internationalization in economics
and security. Where internationalizing models were stronger politically,
departures from nuclear claims were sustained even where the security
context remained challenging, as in Japan, South Korea, and Taiwan. Weaker
internationalizing coalitions in Iran, Pakistan, and Argentina and Brazil until
the 1990s were more politically constrained in curbing nuclear programs. A
model’s relative regional incidence influenced nuclear decisions more than a
neighbor’s nuclearization per se.
These MPS help explain why different actors within the same state diverge
in their approaches and preferences regarding nuclear policy; why a state’s
nuclear policies may vary over time as a function of the relative power of
particular domestic forces; why different states vary in their commitments
to increase information, transparency, and compliance with international
commitments; why security dilemmas are sometimes seen as more (or
less) obdurate; why some states rank alliances higher than self-reliance
but not others; when and how hegemonic coercion and inducements are
effective and when they play a secondary or marginal role; why nuclear
weapons’ programs surfaced where there was arguably little need for them
(the Southern Cone or South Africa among others); and why such programs
were obviated where one might have expected them (Vietnam, Singapore,
Jordan, and many others).
The omission of this significant independent variable in first-generation
studies may have led to an overestimation of other causal variables (balance
of power, institutions, norms) and to potential spurious effects. Its inclusion
may improve our understanding of the actual effects of security dilemmas,
international norms, and institutions. This is different from arguing that MPS
are the only relevant variable; only that MPS enable a better understanding
of the relative impact of other variables on nuclear choices. Indeed, several
empirical studies have provided support for a MPS framework (Liberman,
2001; Solingen, 2004, 2007). Potter and Mukhatzhanova (2008, 2010) endorsed
its caution in overestimating the effects of any single causal variable and
its solid grounding in comparative field research and social science theory.
They found it particularly persuasive in accounting for much of the variation over time across and within states. For instance, internationalizing coalitions relinquished the nuclear option even in the absence of alliances (Egypt,
South Africa, Argentina, Brazil). The centrality of MPS is especially notable
since the evidentiary dice (archives, statements, etc.) is loaded against ulterior domestic political justifications. Leaders have incentives to cast decisions

Why do States Pursue Nuclear Weapons (or Not)

9

favoring or rejecting nuclear weapons as “reasons of state” invoking national
security, international institutional incentives, or normative considerations.
Hence, whereas nuclear behavior provides neorealism with “most likely”
conditions for supporting its tenets, it offers “least likely” conditions for corroborating a MPS argument. Consequently, empirical support for findings
along these lines gains particular significance in this unfriendly terrain.
MPS may not capture all the correlates of nuclear preferences and are, after
all, only ideal types, conceptual constructs rather than historical or “true”
realities. As such, they need not fit every case or indeed any particular case
completely (Eckstein, 1975), but rather provide a heuristic, a helpful shortcut, and a fruitful comparative framework capable of reducing a complex
reality down to some fundamentals. Propositions derived from a MPS framework remain bounded in three ways: with respect to conditions of necessity
and sufficiency in developing nuclear weapons; the incidence of compatible
models in the region; and temporal sequences in the acquisition of nuclear
weapons. Eliminating existing weapons may be more costly politically than
eradicating precursor programs, as stipulated by prospect theory, and the
incentives emanating from the global political economy may operate more
forcefully both at earlier stages in the inception of internationalizing models
and earlier stages in the consideration of nuclear weapons. These hypotheses
remain subject to further investigation.
RECENT RESEARCH DEVELOPMENTS
There has been a significant shift across the methodological range toward
theorizing and testing the role of domestic political drivers to a much greater
extent than was the case two decades ago. The international relations theory
toolkit for studying nuclear decision-making is far more sophisticated theoretically and more diverse methodologically. However, it still suffers from
weak efforts to rely on complementary methods, to explore linkages across
perspectives, and to envisage scope conditions for the operation of different
variables across time and space. The absence of a more analytically eclectic
approach (Sil & Katzenstein, 2010) has hindered the field as a whole, with
works too often speaking past rather than building on one another.
In particular, the last decade has witnessed the newfound application of
quantitative methods to gauge the nuclear motivations of states. Jo and
Gartzke (2007, p. 186) downplay the general role of domestic political
factors––regime type plays no role in the initial decision to nuclearize. Their
study is in many ways an affirmation of the neorealist argument: states’
willingness to seek nuclear weapons is linked to “external concerns,” and
especially to “countervail conventional disadvantage.” Singh and Way
(2004) not only similarly highlighted the external threat environment, but

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also found support for the propositions that “the process of economic
liberalization is associated with a reduced likelihood of exploring nuclear
weapons;” that “economic openness has a statistically significant negative
effect across all three levels of proliferation” (i.e., exploring, pursuing, or
acquiring them); and that “economic liberalization dampened the risk” of
states deciding “to explore seriously the nuclear option” (pp. 876, 878). This
study also recognizes that the connection might have been even stronger,
had cases of states that abandoned nuclear programs been included. Also
excluded were prospective efforts to enhance economic openness and attract
foreign investment, which are the crucial drivers in MPS arguments. There is
no one-to-one correspondence between incentives and efforts to open up the
economy at time T and measures of trade openness at T+1. Fuhrmann and
Li (2008) found that economic liberalization had a positive and statistically
significant effect on nuclear-weapon-free zone treaty ratification as well.
Yet, the process by which those treaties emerge suggests the possibility of
selection effects.
Overall, the quantitative turn has done little to settle debates regarding
state motivations to acquire or renounce nuclear weapons. Given their
disparate findings, the diversity of datasets, coding rules, and statistical methods has only served to muddle the waters; furthermore, the
operationalization of variables failed to capture the nuance of some theories,
undermining the robustness of their conclusions (Montgomery & Sagan,
2009; Sagan, 2011). Many studies, for instance, rely on the Composite Index
of National Capabilities in order to measure state power. Yet, such an
operationalization obscures the subjectivity inherent in notions of power,
overlooking the role of different domestic actors in shaping the definition
and perception of threats. The notion of institutional effects is oftentimes
reduced to NPT membership, severely underrepresenting the depth of the
nonproliferation regime. The negative correlation between existing levels
of trade openness and nonproliferation in some studies is curious, but
quantitative studies are ill-suited to make causal claims about the nature of
ruling coalitions, their expected utilities, the crucial role played by regional
coalitional homogeneity/heterogeneity, and the implications of all these for
the pursuit or renunciation of nuclear weapons.
Several recent works have infused social psychology into the study of
proliferation, following the broader constructivist turn in international
relations theory. Long and Grillot’s (2000) overview of South African and
Ukrainian denuclearization argued that causal beliefs about their respective
Western identities played “a significant role both in preference formation
and strategic choice regarding nuclear policymaking” (p. 36). However, the
conceptualization of these causal beliefs appears overly deterministic and

Why do States Pursue Nuclear Weapons (or Not)

11

inflexible, hardly allowing for the possibility of domestic dissension regarding those identities. South Africa’s Western identity was firmly in place
by the 1940s, they argue, with only slight fluctuations subsequently, while
Ukranian leaders simply began asserting Ukraine’s status as a European
state after independence. Hymans (2006) linked the individual identity of
state leaders—“oppositional nationalists” —with the drive toward nuclear
weapons’ ambitions. Yet, individual psychology as a causal factor presents
significant methodological challenges, including accurate assessment of
the leaders’ presumed profiles. For instance, Japan’s nonnuclear status is
often—wrongly—traced to Premier Sato’s putative antinuclear weapons
commitments (he received the Nobel Prize on that account). But, declassified
records suggest otherwise: Sato conveyed to US Ambassador Reischauer
a personal preference for a nuclear Japan in 1964, oversaw a confidential
inquiry into possible distinctions between offensive and defensive nuclear
weapons in 1967 (the latter allowed by Japan’s constitution according to
some readings), and declared in a 1969 meeting with business leaders that a
defense system was incomplete “if we cannot possess nuclear weapons in
the era of nuclear weapons” (Solingen, 2007, p. 73).
Further exploration of the Japanese case demonstrates the empirical fallacies of attributing nuclear policy to individual psychology. The confluence
of major systemic triggers (North Korea’s repeated nuclear and missile tests,
the rise of China, conflict over the Senkaku/Diaoyu and Takeshima/Dokdo
islands) and strong conservative leaders at Japan’s helm have not yielded
the shifts expected by personality—or neorealist—variables (Mearsheimer,
1981). The succession of a large number of premiers over decades—with a
wide range of personalities and psychological identities—has yielded the
same outcome thus far. This includes the “most-likely” (ideational) cases
of Premiers Fukuda Yasuo, Aso Taro and Abe Shinzo, the latter an ardent
conservative nationalist at heart who learned about Japanese strategic
options at his grandfather’s (Kishi’s) knee. Yet, he did not move Japan
beyond the nonnuclear principles in his first term or even his second, after
North Korea tested nuclear weapons three times, once under his watch.
Abe reaffirmed Japan’s nonnuclear status, aware of the economic, political,
regional, and global requirements without which Japan’s survival in the
twenty-first century global political economy could not be guaranteed.
Such deficiencies of personality-based approaches led Rublee (2009) to link
nuclear forbearance to the international social environment, highlighting
mechanisms of persuasion, social conformity, and identification. Yet, despite
her acknowledgment that “some segments of a state may be more susceptible than others” (p. 5), her treatment of domestic politics remains imprecise.
The discussion of social costs can also obscure the connection of nuclear
issues to other domestic concerns, leading to seemingly inconsistent policies

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that are more difficult to reconcile with identity-based factors. For instance,
despite Sato’s chronicled private inclinations toward nuclear weapons’
acquisition, his foremost political purpose was Okinawa’s reversion to
Japan––a goal he was prepared to advance even if it meant accepting the
formal adoption of the nonnuclear principles in exchange for the Diet’s
approval of his Okinawa agreement. As available historical data suggest,
political survival models and “audience costs” considerations appear to
have neutralized other proclivities that Kishi, Yoshida, Sato, Nakasone,
Aso, or others have had and expressed publicly. Ultimately, the ideational
qualitative studies vary in the extent to which they contend seriously with
competing hypotheses and are amenable to systematic testing.
THE AGENDA AHEAD
The classic perspectives remain very much part of the menu in the study
of nuclear behavior. However, a future agenda should move beyond
indeterminacy, tautologies, or posthocism. Studies along neorealist lines
must cast their arguments precisely and in falsifiable terms; grapple with
more precise notions of power and vulnerability; further stipulate the
impact of alliances and hegemonic guarantees; and specify threshold
conditions for nuclear breakout. Given their systemic assumptions, they
must explain variation in nuclear behavior independently of domestic or
other auxiliary considerations extraneous to structural (relative) power.
Studies advancing neoliberal institutionalist perspectives must expand the
empirical base for stipulating causal linkages between regime membership
and nuclear decisions; address the problem of selection effects through
counterfactual analysis of decisions in a hypothetical environment free of
NPT commitments; and reconcile the presumption of Pareto-optimality
with the reality of power hierarchies in the NPT (Wan, 2014a). Constructivist work must distinguish across nuclear norms (acquisition, use, etc.);
explain the resilience of advocacy for nuclear weapons in nuclear weapons
states and some nuclear aspirants; improve our understanding of selective
socialization into antinuclear weapons norms; explain clustered regional
behavior toward or away from nuclearization under the shadow of the
same international norm (or, why has the norm diffused selectively); and
complement normative accounts of nuclear weapons’ acquisition or rejection
with a theory of domestic politics (or, what explains domestic receptivity
to some norms but not others) that may explain barriers to norm diffusion.
Political survival models must improve classification of coalitions along the
internationalizing/inward-looking spectrum; estimate thresholds beyond
which coalitional shifts might overturn a trajectory toward or away from
nuclear weapons (in other words, when can path-dependence dominate

Why do States Pursue Nuclear Weapons (or Not)

13

coalitional tendencies); and consider the impact of world-time––and an
evolving global economy––on the character of coalitions.
Analysis of nuclear behavior that is attentive to complexity—interaction
among variables—and to historical context can enhance both historical accuracy and predictive capabilities. As Philip Tetlock’s (2005) masterful treatise
on expert political judgment and prediction suggests, parsimony can be the
enemy of accuracy, a substantial liability in real-world forecasting. Quantitative work should be more attentive to the inclusion of relevant cases only
(Cape Verde does not add much validity to a database on this topic); improve
the fit between variables and conceptual arguments; harmonize databases;
and integrate more recent and sophisticated arguments from the overarching international relations toolkit. Qualitative studies should improve the
criteria for case selection, seeking crucial cases and least likely conditions
that force the empirical analysis to overcome difficult conditions. Cases that
feature a reversal of course in either direction seem especially fruitful analytically, the various periods of fluctuation enhancing the number of observations and the opportunity to gauge variation over time. Nuclear outcomes
may be conceptualized not as finite and final but as malleable and operating
on a continuum.
One may find an approach reasonably persuasive in explaining the past, but
it does not necessarily follow that it will also apply in the future. Nonetheless, causal theories must be able to lay out a priori what kind of evidence
would question or corroborate their expectations. They must avoid suggesting many outcomes that would all be consistent with one particular value
of their key variable, to elude the problem of multifinality. Clarity is a sine
qua non for avoiding circularity and ex post facto rationalizations (such as
“state x went nuclear because of acute insecurity,” whereby a nuclear test is
used to signal a posteriori, retroactively, that an acute threshold of insecurity
has been crossed). Arguments must be cast in falsifiable terms a priori, with
more clearly defined and testable propositions. Sensitivity to these and other
conceptual and methodological issues described above can lead to analytical progress and offer better policy insight on the processes and mechanisms
that drive the nuclear behaviors of states.
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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

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FURTHER READING
Potter, W. C., & Mukhatzhanova, G. (Eds.) (2010). Forecasting nuclear proliferation
in the 21st century. Stanford, CA: Stanford Security Studies/Stanford University
Press.
Sagan, S. D. (2011). The causes of nuclear weapons proliferation. Annual Review of
Political Science, 14(1), 225–244.
Solingen, E. (2007). Nuclear logics: Contrasting paths in East Asia and the Middle East.
Princeton, NJ: Princeton University Press.

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WILFRED WAN SHORT BIOGRAPHY
Wilfred Wan is a Japan Society for the Promotion of Science-United
Nations University Postdoctoral Fellow working with the UNU Centre
for Policy Research in Tokyo. He was a 2013–2014 Social Science Research
Council–JSPS Postdoctoral Fellow at Hitotsubashi University. He spent 2
years as a predoctoral fellow with an International Security Program and
Project on Managing the Atom joint appointment at the Belfer Center for
Science and International Affairs (Harvard Kennedy School), including one
as a Stanton Nuclear Security Fellow. He is also a former Institute on Global
Conflict and Cooperation Dissertation Fellow. He has co-authored a chapter
in Sanctions, Statecraft, and Nuclear Proliferation (Cambridge University
Press).
ETEL SOLINGEN SHORT BIOGRAPHY
Etel Solingen is the Thomas T. and Elizabeth C. Tierney Chair in Peace Studies at the University of California Irvine and former UCI Chancellor’s Professor and President of the International Studies Association. Her book Nuclear
Logics: Contrasting Paths in East Asia and the Middle East (Princeton U.P.)
received the APSA’s 2008 Woodrow Wilson Foundation Award for the best
book in all fields and the 2008 APSA’s Robert Jervis and Paul Schroeder
Award for the best book on International History and Politics.
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Why do States Pursue Nuclear Weapons (or Not)