Why have nuclear weapons not been used in war since 1945? This longstanding tradition of nuclear nonuse is particularly puzzling when one considers that in the beginning of the nuclear era, it was widely assumed that nuclear weapons would become a standard feature of modern warfare. U.S. President Dwight D. Eisenhower declared at a press conference in 1955 that he believed that nuclear weapons should be “used just exactly as you would use a bullet or anything else” (p. 9).
In her excellent book on the subject, Nina Tannenwald argues that the answer to this question can be found in the nuclear taboo: a normative prohibition against nuclear use. Tannenwald argues that over the course of the nuclear era, a normative stigma attached to nuclear weapons led to the widespread view that the use of nuclear weapons is simply unacceptable. This stigma has prevented the use of nuclear weapons even in situations in which a nuclear attack may have carried a strategic advantage.
Tannenwald argues that the primary counterexplanation, nuclear deterrence, cannot account for the tradition of nonuse. A deterrence explanation would posit that states have not used nuclear weapons because they feared nuclear retaliation. Yet, Tannenwald argues, nuclear deterrence cannot explain why states have refrained from using nuclear weapons against nonnuclear opponents, such as U.S. nuclear restraint against North Vietnam during the Vietnam War. Tannenwald's theoretical depiction of the realist alternative, however, is overly simplified. There are a number of strategic reasons why states may not want to use nuclear weapons in a particular situation, including the fear of provoking a military intervention from another great power. Fortunately, Tannenwald considers these other strategic costs, including the possibility of great power military intervention, in the empirical chapters.
Tannenwald's evidence for the existence of a taboo consists of a number of case studies of U.S. conflicts with Japan (1945), Korea (1950–53), Vietnam (1964–73), and Iraq (1991). Tannenwald finds support for her argument when U.S. officials engage in “taboo talk.” Taboo talk occurs when U.S. officials articulate concerns about moral costs when calculating whether to use nuclear weapons in a given circumstance. The case studies convincingly show that moral considerations have had an important role to play in U.S. nuclear decisionmaking.
In chapters interspersed with the case studies, Tannenwald also provides a historical account of the origins of the taboo. She shows that the taboo, in fits and starts, gained strength over time, emerging as a mere regulative effect (U.S. officials worried that nuclear use would not be well received by international and domestic audiences) and eventually becoming a constitutive effect (U.S. officials came to believe that nuclear use was inconsistent with the U.S.'s identity as a “civilized” state). The explanation for the origin of the nuclear taboo, while descriptively rich, is less parsimonious than the theory of its effects. A laundry list of factors are responsible for the taboo's emergence, according to the author, including the global antinuclear weapons movement, the interests of nonnuclear weapon states, the moral concerns of individual decisionmakers, the difficulty of mastering nuclear technology, the reconstruction of humanitarian norms since 1945, the democratic nature of the first nuclear weapon state, and Cold War power politics (pp. 20, 365–66).
This book provides a compelling answer to an important, but understudied, question with unquestionable real-world significance. Furthermore, Tannenwald's account of the nuclear taboo marks a significant contribution to the theoretical literature on the constraining effects of norms in the international security arena, and to our understanding of the creation and change of international norms.
For example, in a fascinating discussion, Tannenwald highlights U.S. efforts to legitimize nuclear use while Washington maintained a position of nuclear superiority, and Soviet countermeasures to foster a nuclear taboo while Moscow lagged behind in a position of nuclear inferiority. Recent scholarship has focused on the role of transnational advocacy networks in propagating international norms, but Tannenwald's analysis reminds us that states can also be effective norm entrepreneurs. The USSR's success in contributing to efforts to delegitimize nuclear use is an important case study for scholars and practitioners interested in understanding how states use soft power to shape the international ideational environment to their strategic advantage.
At times, however, the author's claims go beyond what the evidence will support. Tannenwald clearly wishes to argue that the taboo is a systemic phenomenon (p. 13, 377), but the analysis presented in this book demonstrates that moral considerations have influenced nuclear decisionmaking in the United States only. The brief sketches provided in the conclusion of nuclear policy in other countries are insufficient to support the more ambitious claims about the existence of a global taboo (pp. 377–81). This is both a challenge to, and an opportunity for, the nuclear taboo research agenda. Future scholarship can examine whether, and the degree to which, moral considerations have influenced nuclear decisionmaking in other states.
Similarly, while the author sometimes claims that the taboo was a “particularly salient” (p. 192), or the “key” (p. 126), factor leading to nuclear nonuse in historical cases, the evidence only supports the more modest claim that moral costs were considered alongside other material costs and benefits. In three of the four cases considered, the combined strategic and moral costs of nuclear use appeared to outweigh any perceived strategic benefit, and U.S. leaders kept their fingers off the nuclear trigger. But, an alteration of the strategic parameters might have very well led to a different outcome. Indeed, there is evidence to suggest that even the U.S. leaders who had internalized the taboo to the greatest extent, according to Tannenwald, including U.S. Presidents Kennedy and Johnson, would have used nuclear weapons in dire circumstances, such as a Soviet military invasion of Western Europe (pp. 206, 255).
This raises a key question about the future of the taboo. Tannenwald concludes by listing a number of dynamics that could undermine the norm of nonuse (pp. 383–87). Indeed, one comes away from the book with a sense that the taboo may be extremely fragile. This should be a cause of concern for both antinuclear activists and for strategists in the U.S. government. Given its vast conventional military superiority, the United States may benefit more than any other state from the existence of a global nuclear taboo.
