The Hegemon’s Tool Kit: US Leadership and the Politics of the Nuclear Nonproliferation Regime,

Rebecca Davis Gibbons has published several notable articles examining the role of great powers in the global nuclear order over the past few years (e.g. Gibbons 2019, 2020). Her work has included scholarly research on supply-side nuclear restrictions, promotion of nonproliferation agreements and institutions, and interaction with the Treaty on the Prohibition of Nuclear Weapons (TPNW). In her first book, Gibbons puts all of these pieces of the puzzle together. The Hegemon’s Tool Kit offers a broad and elegant theory of international nuclear politics that should be of great interest to readers of this journal.

Gibbons makes clear from the outset that her theory is one of “regime adherence” (p. 3). Specifically, her book seeks to explain why countries accept different elements of the regime surrounding the Treaty on the Nonproliferation of Nuclear Weapons (NPT). Gibbons is primarily interested in three components of the nonproliferation regime: the 1968 NPT itself (pp. 72–111), its 1995 indefinite extension (pp. 112–142), and the International Atomic Energy Agency’s 1997 Model Additional Protocol (pp. 143–162). The answer to why countries adhere, Gibbons finds, has to do with US promotion of the regime (p. 36). Gibbons’ work thus offers a fitting addition to recent literature on Washington’s efforts to expand NPT membership (Hunt 2022) and secure the treaty’s extension (Onderco 2021).

The central focus of the theory is on “a state’s level of embeddedness within the overall US-led global ordering project” (p. 22). Closeness – or aspiring closeness – to Washington endows US leaders with diplomatic leverage over other states. The US government can then employ a spectrum of tools to convince countries to take part in institutions of the nonproliferation regime. Such tools range from “low-cost diplomacy”, like simple requests and démarches aimed at allies, to outright “coercion” against US adversaries (p. 26). If one tool fails, Washington has the ability to escalate if desired. In practice, of course, commitment to the regime has varied across US presidential administrations (p. 69).

To demonstrate the logic of the theory, Gibbons explores five countries’ histories in the nonproliferation regime: Cuba, Egypt, Indonesia, Japan, and South Africa. Gibbons shows how the United States was able to use the aforementioned tools either successfully or unsuccessfully vis-à-vis these states as it attempted to expand the regime. The cases draw on rich historical details, including many primary source documents. These narratives are a contribution to the literature in themselves and should be useful in the classroom for instructors of nuclear politics. Moreover, through careful process tracing of both positive and negative cases, Gibbons is able to illuminate causal mechanisms underlying state decisions.

Some of Gibbons’ cases are hard tests of the theory. Egypt and Japan are states that considered developing the bomb at different points of the Cold War (Bleek 2017), so their willingness to embrace the NPT in response to a variety of US tools demonstrates the robustness of the theory. Likewise, Cuba’s decision to reverse course on over three decades of opposition to the NPT, by acceding in 2002, suggests just how effective hegemonic power can be over states that are antagonistic to the liberal international order. In each case, Gibbons also weighs evidence for embeddedness against three alternative explanations: security, fairness, and domestic political economy (pp. 29–32). She concludes, however, that hegemony is the dominant driver in state decisions.

Gibbons’ argument is compelling, but there are some areas where further refinement would be useful. For instance, she defines the security-based alternative explanation as being about a state’s willingness to join the NPT “if their neighbors or adversaries do the same” (p. 30). Since Israel and China had not joined the treaty at the time, closeness to the United States would therefore be a better guide to why Egypt and Japan accepted the NPT than security rationales. Yet, Cairo was interested in obtaining US military aid, and Tokyo received enhanced US defense assurances. Both cases point to Washington as a patron that could alter the regional balance of power and suggest that this definition of security is overly narrow. Gibbons’ mention of US attempts to secure Trinidad and Tobago’s NPT adherence, however, is a case where security dynamics almost certainly were not pivotal (p. 19). To the author’s credit, security issues are obviously part of states’ relationship with the hegemon. This could be disaggregated in future work.

Further, while the book makes a persuasive case for the central role of the United States, it sometimes underplays efforts other states made to encourage regime adherence. Gibbons offers a lengthy discussion of why Washington was far more influential than Moscow in promoting the NPT and related institutions (pp. 36–71). This is historically difficult to deny regarding the treaty’s indefinite extension and the propagation of the Model Additional Protocol for safeguards. But in the case of early NPT ratifications, the Soviet Union played a major role (Coe and Vaynman 2015). Just as the Americans could use tools in their sphere of influence, so too could the Soviets (Timerbaev 1999). It is unlikely that US activities alone would have made much headway expanding the regime to the Eastern Bloc during the Cold War. There were also extensive efforts by states from the Global South – many horrified by the bipolar nuclear standoff – to promote the nonproliferation regime (e.g. Rodríguez Aquino 2020). They continue in the context of the 2017 TPNW.

These points notwithstanding, Gibbons has written a powerful book that should find its way into the hands of scholars and policymakers alike. Its message is somewhat pessimistic but rings through very clearly. That is, nuclear nonproliferation does not just happen because of global norms and international law. It requires the interest and careful planning of the hegemon. Gibbons therefore cautions readers that emerging multipolarity may present considerable challenges to the regime as US power wanes (p. 169). Seen in the context of current events, two important questions arise. First, how will the nonproliferation regime cope with Russia’s war on Ukraine and its implications for the global nuclear order?¹ Second, can the relatively new TPNW be successful if the hegemon continues to oppose it?

Only the future will reveal the efficacy of the nuclear nonproliferation regime relative to the strength of US promotion efforts. But for those wondering about how the international community arrived at its current nuclear rules of the road, Rebecca Davis Gibbons has helped to provide a map. Today’s media landscape is filled with constant warnings of nuclear threats and proliferation; the need for US leadership in nuclear diplomacy is acute. To understand how and why that has historically succeeded or failed, readers should check out The Hegemon’s Tool Kit.

Notes

¹ For early scholarly thinking on this issue see, e.g. Brewer, Miller, and Volpe (2022), and Bollfrass and Herzog (2022).