In The Logic of American Nuclear Strategy, Matthew Kroenig observes a puzzling disjuncture between scholarship and practice in the realm of nuclear strategy. For much of the nuclear age, the United States has sought to achieve “superiority” over its adversaries, maintaining a large, elaborate, and technologically sophisticated nuclear stockpile. Yet a coterie of academic luminaries—including Thomas Schelling, Kenneth Waltz, Robert Jervis, and Charles Glaser— have long criticized this doctrine as both frivolous and dangerous, arguing that deterrence requires only a small and secure nuclear arsenal. Why has US nuclear strategy not followed this prescription?
Although it begins with an intriguing puzzle, the book does not attempt to answer it. The Logic of American Nuclear Strategy does not, in fact, explain the logic driving US nuclear strategy. It does not investigate why the United States has opted for an arsenal of thousands of nuclear weapons deployed on a multitude of advanced delivery platforms. Nor does it explain why the United States has prioritized superiority during some periods but not others. Instead, its purpose is to devise a rationale, rather than an explanation, to justify America’s quest for nuclear supremacy.
The book’s central claim is that nuclear superiority—which it defines as simply having more nuclear weapons than one’s adversary (p. 68)—gives leaders bargaining advantages in nuclear confrontations. It draws heavily from the scholarship of Schelling, who articulated in The Strategy of Conflict (1960) how leaders can translate nuclear weapons into political leverage. In high-stakes confrontations, Schelling argued, a sane leader cannot credibly threaten to intentionally start a catastrophic, suicidal nuclear war. But leaders can and do take risky actions that increase the chance of a nuclear war occurring by accident or mistake. Who prevails in a nuclear crisis depends on which side has more nerve in this escalating game of brinkmanship; in other words, who has more resolve in the face of unpredictable danger.
Kroenig makes a minor but important modification to Schelling’s argument: he asserts that resolve is directly tied to the balance of nuclear forces. A state possessing a nuclear advantage is willing to run higher risks of nuclear conflict than its opponent, Kroenig argues, because it would suffer comparatively less damage in a nuclear war. Consequently, he claims, nuclear-superior states are more likely to prevail in international crises because they are willing to stand firm when others are not. Several chapters of the book find support for this claim in quantitative analyses and brief vignettes of four international crises. Armed with these findings, the book concludes with a lengthy Pentagon shopping list, calling for hundreds of new nuclear warheads, a new nuclear earth-penetrating weapon, more accurate ballistic missiles, new cruise missiles, and a variety of additional missile defense capabilities.
The Logic of American Nuclear Strategy follows in the footsteps of nuclear hawks who advocated a doctrine of nuclear superiority in the 1970s and 1980s. But although it arrives at the same conclusion as these scholars, it does not share their theoretical sophistication. The Cold War hawks’ case for superiority rested on the belief that the United States needed a range of flexible nuclear options to be able to deny Soviet war aims at any level of violence. Without this capability, it was feared, the Soviet Union might try to force the United States to capitulate in a crisis or war by using limited nuclear strikes against US conventional forces, holding the rest of its arsenal in reserve to deter retaliation against Soviet cities. Several scholars recently have issued similar warnings about Russia and China. Although their conclusions are contested, these scholars are right to consider whether adversaries might perceive advantages from using nuclear weapons short of all-out nuclear war. Kroenig’s argument, however, neglects this critical nuance. It depicts nuclear conflict only in its least plausible form: as a singular, full-scale nuclear exchange. In this way, it sidesteps the most vexing problems confronting US nuclear planners today.
The book argues that states with larger nuclear arsenals than their adversaries are more likely to prevail in crises because they can inflict comparatively more damage. But it was Schelling who identified the error in this logic in Arms and Influence (1966, p. 36) more than a half-century ago. Schelling pointed out that leaders do not decide whether to escalate a crisis by weighing their expected war costs against those of the other side. What matters is whether one’s costs for escalating are outweighed by the anticipated gains. It is entirely possible, therefore, that a weak state might stand firm against a much stronger opponent if it cares about the stakes enough, as the United States has discovered to its chagrin many times. Powerful states can be sensitive to pain, and weak states can be indifferent to it.
By conflating military capabilities with resolve, The Logic of American Nuclear Strategy paints an incoherent picture of nuclear crisis bargaining. If the theory were correct, adversaries could simply compare nuclear arsenals during a crisis, and the weaker side would capitulate, recognizing that it could not escalate further than its opponent. But this raises awkward questions for the theory. Most importantly, why would the weaker state enter such a crisis in the first place? The book devotes an entire chapter to assessing relative nuclear capabilities with open-source information; presumably leaders could perform the same exercise to avoid crises they are destined to lose. The author’s formalization of the theory, published elsewhere but referenced in the book, does not solve the problem, because it simply stipulates the existence of a crisis rather than modeling participants’ choices to initiate it. The fact that nuclear crises occur at all is confounding for the theory.
A natural reply to this objection is that the true nuclear balance is difficult to ascertain, so perhaps states escalate crises with misguided optimism about their relative capabilities. Once they realize their nuclear inferiority, they back down. This is a plausible argument (although Kroenig does not make it), but it creates a new problem: if a crisis occurs because of inaccurate beliefs about the nuclear balance, how does crisis bargaining correct them so that the crisis can end? Does brinkmanship somehow help states learn new information about the relative nuclear balance? If so, the book does not explain how.
Ultimately, this is the fatal flaw in Kroenig’s theory: by defining resolve in terms of material capabilities, it misses the essence of crisis bargaining. If capabilities and resolve are the same thing, then when the nuclear balance is known, nuclear crises should not occur at all. Conversely, when the true balance is not known, then it cannot shape leaders’ decisions to back down or escalate, and therefore it cannot determine who prevails. Either way, the theory culminates in a logical dead end.
Still, it could be the case that nuclear-superior states historically achieve better foreign policy results. If so, however, the book does not make a convincing case for this result. The quantitative analysis of crisis outcomes, based on just 20 crises, relies heavily on idiosyncratic data adjustments, questionable case selection, and disputed historical interpretations. The case vignettes, moreover, do not provide evidence that beliefs about comparative nuclear damage, as opposed to absolute capabilities, drive crisis escalation decisions. In the end, although the book aspires to provide guidance to US practitioners of nuclear policy, its theoretical and empirical foundations are too shaky to justify its fervent conclusions.
