SSU Forum/ The 13th Yamakawa Kenjiro Memorial Lecture/ GraSPP Research Seminar
with Associate Professor Alexandre Debs

Date: Wednesday, December 19 2018, 12:45-14:15
Venue: SMBC Academia Hall, 4F International Academic Research Building,
the University of Tokyo
Subject: "The Strategic Causes of Nuclear Proliferation: Northeast Asia in Comparative Perspective"
Speakers: Alexandre Debs, Associate Professor, Political Science, Yale University
Comentator: Shuhei Kurizaki, Associate Professor, Faculty of Political Science and Economics, Waseda University
Moderator: Nobuhiro Hiwatari, Professor, Political Science Institute of Social Sciences, The University of Tokyo
Language: English
Co-hosted by: Security Studies Unit, Policy Alternatives Research Institute, the University of Tokyo
The Whitney and Betty MacMillan Center for International and Area Studies at Yale/ FUTI (Friends of UTokyo, Inc.)
GraSPP Research Seminar, the University of Tokyo
Abstract: This presentation introduces a strategic framework to understand the causes of proliferation, and the effectiveness of counterproliferation tools, placing Northeast Asia in comparative perspective. Acquiring nuclear weapons takes time and effort. Before a nuclear-weapons program comes to fruition, adversaries and allies may offer threats and assurances to prevent proliferation. The stronger is a potential proliferator, the more likely it is to succeed in its attempt to acquire nuclear weapons. Threats are most effective against weak potential proliferators, and assurances are most expedient when offered to strong potential proliferators. In Northeast Asia, threats of preventive war have been ineffective in preventing North Korea from acquiring nuclear weapons, given its ability to inflict severe damage on Seoul. Assurances have been crucial in getting South Korea and Japan to forgo nuclear weapons. Looking ahead, a coercive approach toward North Korea is unlikely to be effective, and questions about assurances offered to South Korea and Japan risk spurring their proliferation.
Biography: Dr. Alexandre Debs is Associate Professor of Political Science at Yale University. His research focuses on the causes of war, nuclear proliferation, and democratization. His work has appeared or is forthcoming in the American Political Science Review, the Annual Review of Political Science, International Organization, International Security, International Studies Quarterly, the Journal of Conflict Resolution, the Journal of Politics, and the Quarterly Journal of Political Science, among other outlets. He is the author of the book Nuclear Politics: The Strategic Causes of Proliferation (with Nuno Monteiro), published by Cambridge University Press in 2017. Alexandre received a Ph.d. degree in Economics from M.I.T., an M.Phil. in Economic and Social History from the University of Oxford as a Rhodes scholar, and a B.Sc. in Economics and Mathematics from Universite de Montreal.

The Security Studies Unit of Policy Alternatives Research Institute (PARI), in collaboration with The Whitney and Betty MacMillan Center for International and Area Studies at Yale FUTI (Friends of UTokyo, Inc.) and the Graduate School of Public Policy (GraSPP) hosted a timely talk with Prof. Alexandre Debs, Associate Professor of Political Science at Yale University.

The session was chaired by Prof. Nobuhiro Hiwatari, Professor at Political Science, Institute of Social Sciences at the University of Tokyo. Prof. Shuhei Kurizaki, Associate Professor at the Faculty of Political Science and Economics at Waseda University served as a discussant.

Prof. Hiwatari opened the meeting by introducing the speakers.

Prof. Debs began his presentation with a gracious acknowledgement of the wealth of knowledge about nuclear proliferation in the region among the audience members. His presentation was based on the key arguments presented in his book co-authored with Prof. Nuno Monteiro, titled, “Nuclear Politics: The Strategic Causes of Proliferation” and articles published in leading journals over the years. His talk revolved around the puzzle of why some countries are able to acquire nuclear weapons. To that end, the presentation addressed the following questions. What explains the history of nuclear proliferation, in general and in Northeast Asia in particular? What will be the effect of nonproliferation threats and assurances in Northeast Asia?

Understanding proliferation is a major question in the field of International Relations. Typically, scholars struggle to come to an understanding as to why some countries acquire nuclear weapons and some do not. A favored existing explanation is that nuclear weapons serve as the ultimate deterrent and thus provide security benefits. This approach, Prof. Debs argued, over predicts proliferation, failing to explain why despite its obvious benefit of providing security to many states, too few have acquired them. Making sense of this puzzle is important not only for academic but policy purposes as well. The current interaction in the standoff between North Korea, and South Korea and the United States, Prof. Debs pointed out, illustrates the challenge of identifying appropriate policy responses—what would be the effects of threats to North Korea and assurances to allies in Northeast Asia at present, as well as preventing proliferation in the region in the future?

Revisiting the argument that security provides the necessary and sufficient cause of nuclear proliferation, Prof. Debs argued that while a state wishing to acquire nuclear weapons may gain advantage over an adversary, other states may counter the move by threats or assurances to prevent her from getting weapons. In game-theoretic terms, this could be translated as a costly investment with delayed returns. Following this line of reasoning, when might a state seek nuclear weapons?

Prof. Debs introduced the variable of willingness on a state’s part to bear the cost of acquiring weapons in the face of pressure from other states. The willingness constraint of a state could be defined in terms of a significant security threat, which cannot be met through conventional security weapons alone. Or, that the state lacks assurances from allies of common defense against potential security threats to it. Yet, the willingness of a state is not sufficient—other states may conduct preventive action against the potential proliferator by attacking or posing a credible threat. Thus, in addition to the willingness of the potential proliferating state, it also has to overcome the opportunity constraint. The opportunity constraint is understood in relation to counter proliferation efforts by other states. These states or the adversary state may either issue a credible threat of military strikes or launch actual attacks against the potential proliferating state’s nuclear program. The potential proliferating state has better chances of acquiring weapons if it has strong military capabilities to deter attacks or has a reliable nuclear ally in the case of potential attacks by adversary state(s). Although nuclear weapons are weapons of weak states, they cannot acquire them easily, being vulnerable to pressures posed by counter proliferating states.

Bringing these concepts within the history of proliferation in the region through the security perspective, Prof. Debs pointed out that North Korea, having conventional capabilities to wreak destruction in Seoul, was able to acquire weapons in the 1990s. This was on account of the fact that launching a preventive attack on North Korea was a costly enterprise for the United States. As a result, despite the pressure put on North Korea by the United States, the threat of attack was not credible. South Korea and Japan on the other hand, have not invested in efforts to acquire nuclear weapons as they share a long-standing security commitment with the United States. In the 1960s, however, when President Nixon introduced the Guam Doctrine that aimed at encouraging allies in the region to assume more control of their security, fears of potential abandonment led South Korea to consider acquiring nuclear weapons. This linkage between the American strategy and potential proliferation in the region resulting from a sense of insecurity led to a shift in policies. Allaying these concerns by the United States contributed to South Korea abandoning its nuclear aspirations in the early 1980s.

Within the ambit of current realities vis-à-vis North Korea, Prof. Debs argued that the threat of preventive war against the country does not present a credible option since the United States has not shown willingness to get involved to a great extent. As a result, North Korea will not be deterred to abandon its nuclear program. At the same time, doubts about long-standing commitments of security provided by the US to its allies increase the risk of proliferation in the cases of South Korea and Japan—preventing states to acquire nuclear weapons requires credible assurances.

In the remainder of the talk, Prof. Debs explained the theory of nuclear proliferation through two models highlighting strategic interactions among states that help understand why some are able to acquire nuclear weapons and others fail to do so.

In the first model, there are two players including Potential Proliferator (P), and Adversary (Ad). The Potential Proliferator (P) has to take preventive strikes by Adversary (Ad) that come at a cost c(m), in account in its decision calculus to produce the effect e(m) of acquiring weapons. The cost of proliferation depends on conventional military capabilities (m); the greater the military capabilities (m) of the Potential Proliferator (P), the greater the cost c(m) of preventive war since (P) can protect its nuclear program. A weak state’s military capabilities (m) tend to be weaker, thereby increasing the effect of proliferation.

Consider the extreme situation, where there is perfect information about the intent of the potential proliferator through reliable intelligence reports or public signals. Proliferation may take place only when both the willingness and opportunity constraints are met. The willingness constraint is met when the effect (e(m)) of acquiring weapons is higher than the cost of investment (k) for the Potential Proliferator (P). The opportunity constraint is met when the effect (e(m)) of acquiring weapons is lower than the cost of preventive war (c(m)) for the Adversary (Ad). In sum, among states that are willing to acquire nuclear weapons, nuclearization is likely in the case of strong conventional military capabilities of the Potential Proliferator (P), since in this case the cost of military attack c(m) for the Adversary (Ad) is too high to rationalize a preventive attack. Put differently, although nuclear weapons are weapons of the weak, yet they seldom manage to acquire them.

In the second model, the number of players increases to include an ally state (Al) of the Potential Proliferator (P). An ally (Al) could decide to fight alongside the proliferator by providing support (st), thereby producing the same effect as the Potential Proliferator (P)’s military capabilities. The cost of preventive attacks against the Potential Proliferator (P) increases if the ally supports P, and the effect of proliferation is reduced if the ally is expected to support P in the future.

The likelihood of proliferation in this model rests on strategic interactions among Potential Proliferator (P), Ally (Al), and Adversary (Ad). A Potential Proliferator (P)’s decision to engage in proliferation in this model depends on the moves by the ally (Al). In one scenario, the prospects of proliferation may increase since the Potential Proliferator (P) is assured of support from the ally (A) in case of preventive attacks or increased cost of attacks c (m) for the Adversary state (Ad). In the second scenario, the presence of an ally (Al) may reduce prospects of proliferation on account of the security umbrella (future support or st+1) it provides to the Potential Proliferator (P), thereby eliminating the willingness constraint.

Within the context of strong and weak states, the presence of an ally has differential effects. A strong Potential Proliferator (P) may forgo nuclear weapons on receiving security assurances from an ally (Al). A weak Potential Proliferator (P) on the other hand may have increased prospects of engaging in proliferation since it has support from an ally (Al) in case of attacks as well as that the cost of preventive war c(m) increases for the Adversary (Ad). An ally (Al)’s policy tool kit, on the other hand, may include assurances and threats. Assurances work best with strong states, eliminating the willingness to acquire weapons. On the other hand, threats of abandonment are effective with weak states, thereby reducing the opportunity of the latter to engage in proliferation.

Prof. Debs illustrated the key principles of the theory through empirical cases in history. First, the ten countries that have acquired nuclear weapons illustrate the point that states facing high levels of security threats engage in proliferation (United States, Soviet Union, China, South Africa, India, United Kingdom, North Korea, France, Israel, Pakistan). Second, data corroborates that proliferation is contingent on conventional strength and the support of a nuclear ally. Successful preventive attacks or threats of preventive attacks were carried out against weak states with no nuclear allies (Iran, Iraq, and Syria). On the other hand, the support of an ally created space for weak states to engage in proliferation. For instance, Pakistan during the 1980s served as a key state for US interests in the Afghan war; it is during this time that it developed its capabilities to a considerable extent. Similarly, France and the United Kingdom acquired weapons on account of protection provided by the United States. Third, potential abandonment, a coercive strategy, by a nuclear ally may deter states from seeking nuclear weapons (Taiwan and West Germany serve as examples). Conversely, long-term security arrangements guaranteeing protection by a nuclear ally reduce the prospects of proliferation. In other words, the willingness constraint is not met; Japan and South Korea serve as key examples.

Linking insights from the theory of proliferation to future trends in the region, especially vis-à-vis North Korea, South Korea and Japan, Prof. Debs concluded that threats were unlikely to obtain North Korea’s denuclearization as they lack credibility. In the cases of South Korea and Japan, the security umbrella offered by the United States has until now prevented the two states to engage in proliferation. Yet, doubts about US assurances, especially considering the current political climate in the country, raise the risk of the two states seeking nuclearization.

These projections echo the principles laid out in the book co-authored by Prof. Debs and Prof. Monteiro, which is based on 16 case studies that advance theory by including strategic interactions among potential proliferating states, ally states and adversary states. This approach expands the scope of analysis that has hitherto focused primarily on security concerns of potential proliferators. In doing so, we may can make sense of why and when countries seek nuclear weapons and when assurances or threats are effective.

Prof. Hiwatari thanked the Prof. Debs, and before inviting Prof. Kurizaki to share his comments, he noted the theoretical elegance and empirical comprehensiveness of the presentation.

Prof. Kurizaki briefly contrasted the theoretical model as proposed by Prof. Debs from extant debates preceding his work. The topic of nuclear proliferation has generated extensive research. In the 1990s, for instance, approaches stemming from non-security sources of demand and drawing from constructivist to neoliberal theories, investigated why some countries engage in proliferation and some didn’t. Nina Tannenwald’s authoritative work, for example, focused on nuclear taboos that helped explain why some states did not engage in proliferation as there was a stigma attached to the enterprise. In the 2000s, another branch of IR scholars, including rationalists and game-theorists explored the topic as well, with some focusing on emerging international nonproliferation norms and mechanisms. Prof. Debs’ work differs from non-security explanations and brings security back in as the heart of the matter. The mathematical model developed in his book highlights power transitions and preventive wars. As well, his work highlights how the capabilities of nuclear ally states can both increase or decrease the prospects of proliferation. In sum, the book lays out a beautiful argument.

Prof. Kurizaki also posed questions regarding how one could explain regional variations when applying the model to realities in Northeast Asia. For instance, threat credibility, a key mechanism in the model could be understood within the context of NATO in Europe. On the other hand, in Northeast Asia, instead of an organization like NATO, ground realities include fragmented US allies including South Korea, Taiwan and Japan. Second, if precision technology and contingency plan options (for instance, in the example of North Korea) could be included in the mathematical model. Thirdly, why the nuclear strategy for proliferators was not accounted for once they nuclearize in the model, especially considering that some weak states, which do not have the capability of second strike, could potentially use their capabilities towards subversive ends. Lastly, Prof. Kurizaki wondered about the feasibility of nonproliferation considering current realities of the world. Audience members also asked questions about the theory and how it relates to different views on the usefulness of nuclear weapons.

Prof. Debs thanked Prof. Kurizaki and other audience members for their questions, and a lively discussion followed. In particular, Prof. Debs highlighted that there was room for further research on nuclear deterrence. Some have argued that weapons are only good for deterrence while others have suggested that they are also useful for compellence. The model presented in his book side-steps these debates and only assumes that weak states benefit the most from acquiring nuclear weapons is greater, following a broad consensus in the literature. The fact that few weak states have acquired nuclear weapons is a puzzle that formed the driving effort of the scholarly enterprise.

Dr. Hiwatari thanked the discussant stressing that Prof. Debs work is truly impressive in the way its exhaustive empirical scope is constructed by simple, but intuitively sound, elements.