Todd S. Sechser and Matthew Fuhrmann’s new book, Nuclear Weapons and Coercive Diplomacy, provides a compelling and rigorously researched response to the existing literature on the consequences of nuclear weapons in the international system. Anchored in salient contemporaneous debates about what benefits nuclear weapons may actually bestow to their possessors, the authors outline and develop a methodical approach to examining and responding to existing scholarship that yields differing predictions about the utility of nuclear weapons. In addition to systematically addressing some of the theoretical and empirical limitations of this alternative perspective, which they term the Nuclear Coercionist School, the authors develop a compelling new theoretical approach, articulated as the Nuclear Skepticism School, to clearly and persuasively detail why nuclear weapons may not be as useful for coercion (as defined as the use of threats intended to motivate another to act) or bargaining as previously hypothesized. Further, in this laudable undertaking, Sechser and Fuhrmann proceed with a rigorous and exhaustive research design that presents informative statistical tests to decipher general patterns and parallel case studies that carefully trace causal mechanisms and examine potential outliers.

This study provides a welcome response to the existing debate (e.g., see Kyle Beardsley and Victor Asal, “Winning with the Bomb,” Journal of Conflict Resolution 53[2], 2009; Matthew Kroenig, “Nuclear Superiority and the Balance of Resolve: Explaining Nuclear Crisis Outcomes,” International Organization, 67[1], 2013, among others) on how, if at all, nuclear weapons can be used in interstate relations. No doubt, this question and the resulting decades-long scholarship, has been at the forefront of the academic, policy, and military discussions on how nuclear weapons can actually shape interstate relations beyond deterrence. The book also contributes to a growing wave of contemporaneous, mixed-method research on these issues that leverages the advantages of statistical analyses and in-depth case studies to answer challenging questions.

First, the book establishes a carefully-outlined assessment of the core work on nuclear coercion—and why the limitations of this research (i.e., concerns over credibility and brinksmanship) require a different approach to test extant claims. The first objective for Sechser and Fuhrmann is to present an overview of the logic of the nuclear coercionist school, including both how nuclear weapons can actually enable coercers through issuing threats of profound punishment, and how nuclear powers are able to effectively leverage this advantage in diplomacy and bargaining. In clearly stating, often in detail from the original sources, how this approach may not be reflective of the entire universe of nuclear weapons states (especially in examining new nuclear states), the authors are able to identify clear avenues for departure from this research and, more importantly, where their original theory may yield more satisfactory predictions about what nuclear weapons can actually do in world politics. It is through this approach, grounded in the core framework of deterrence and compellence, that Sechser and Fuhrmann persuasively suggest that, under most conditions, nuclear weapons are neither useful for extracting or coercing concessions from adversaries in the midst of a conflict, nor for winning dispute outcomes where the coercer may aim to use military force (including nuclear weapons) for territorial objectives.

Second, this study marshals a research design aimed to provide complete and compelling evidence and to mollify potential concerns regarding statistical and case-based approaches. In doing so, Sechser and Fuhrmann accomplish two goals. First, they are able to demonstrate, with original data on compellent threats and novel empirical tests, that nuclear weapons are not as useful in disputes or diplomacy as previously suggested. Intertwined with these quantitative analyses, the authors also examine some oft-studied cases to assess important patterns, selection effects, or outliers. This exhaustive approach included analyzing nineteen distinct cases of nuclear brinksmanship where nuclear weapons states may have attempted to leverage their nuclear status to coerce concessions or victories from their adversaries. Second, the authors address potential limitations and concerns regarding the use of statistical analyses in nuclear scholarship. In doing so, this book provides an “ideal” research design, useful for Ph.D. students, junior scholars, and others designing their own projects. While their review, and mitigations, of the criticisms of quantitative scholarship is necessarily extensive to appease potential skeptics of their approach, Sechser and Fuhrmann provide a useful template for scholars learning to identify flaws in existing literature and to improve upon these weaknesses in new research.

Despite this important progress made in rigorously analyzing and building upon existing scholarship on the consequences of nuclear weapons, there are still aspects of the discussion left open for debate. Specifically, in thinking through contemporary foreign policy crises among nuclear weapons states, the book left me seeking two additional parts to this story. While already complex in examining how nuclear coercion may be limited in many instances, these absences point to some potential weaknesses with the book and, more importantly, highlight important avenues for further research by the authors or other scholars who are similarly focused on examining the causes and consequences of nuclear proliferation.

First, Sechser and Fuhrmann provide a compelling narrative for why coercion may not be as useful in the nuclear context. However, in this discussion it is less clear how the authors differentiate between immediate and general compellence. Often discussed in the context of deterrence, these distinctions are easily translatable in understanding coercive diplomacy. This nuance may be particularly salient in Sechser and Fuhrmann’s discussion of credibility as a potential constraint on the efficacy of nuclear coercion. It is plausible that adversaries are likely to view general threats of extraordinary punishment to be non-credible and unrealistic. However, it is possible that the marginal effects of nuclear weapons on interstate conflict and diplomacy may depend in part on the nature of the threat—the immediacy of the punishment if the adversary fails to change its behavior. As leaders sometimes employ purposefully vague public declarations to obscure this information (making it challenging for adversaries to gauge its credibility), evidence of successful coercion may require data that is difficult to acquire—namely that leaders in the target state were persuaded by nuclear coercion when the nuclear power could more easily and quickly deliver the punishment if the target refused (i.e. forward deployments, advanced power projection capabilities, the nuclear triad). While unlikely to change the overall findings that nuclear weapons are still less effective for compellence (than deterrence), examining this distinction may help complete the story.

Second, the study doesn’t examine how nuclear weapons may compel non-adversaries. Both in the theory and empirics, the target in question is the adversary. It could be, however, that nuclear weapons have important behavioral effects on other type of states, including allies or clients. Nuclear weapons patrons may be able to wield their nuclear status to compel clients to modify their behavior (i.e., to stave off moral hazard or agency loss). This may be especially effective if the nuclear patron can credibly signal a withdrawal of support if the client does not change its behavior. This tactic may have been useful during the initial phases of the extension of U.S. nuclear umbrella over allies such as Taiwan and South Korea. Regardless, examining nuclear coercion in the context of third parties may help in the search for evidence of nuclear coercion.

Notwithstanding these qualms, this book offers an important and informative reply to the existing scholarship on the consequences of nuclear weapons in world politics. In taking a necessary step forward in rigorously examining these dynamics and dispelling popular myths about nuclear weapons, Sechser and Fuhrmann provide a significant contribution to our understanding of how nuclear weapons may actually shape relations between actors and, more importantly, their limited utility in inter-state conflict.