The Logic of American Nuclear Strategy: Why Strategic Superiority Matters
By Matthew Kroenig
Oxford University Press, 2018
$29.95 280 pp.
Reviewed by Michael Fitzsimmons
Michael Fitzsimmons is a Visiting Research Professor in the Strategic Studies Institute at the U.S. Army War College.
Famously, Henry Kissinger once wondered out loud, “What in the name of God is strategic superiority? . . . What do you do with it?” Over 40 years later, the questions still resonate, and Georgetown University professor Matthew Kroenig aims to tackle Kissinger’s quandary. The Logic of American Nuclear Strategy begins with a puzzle: if the basic premise of U.S. nuclear deterrence strategy is supposed to be that the United States can survive a massive nuclear attack and retaliate with great force (so-called assured destruction), why have successive Presidents maintained nuclear capabilities that go well beyond what is required for this goal?
Robert Jervis asked this same question back in 1984 in a book titled The Illogic of American Nuclear Strategy (Cornell University Press, 1984). His answer was—more or less—that policymakers do not understand what they are doing. Kroenig’s book serves, in part, as a rebuttal to Jervis’s argument.
Of course, the issues here are far from just a rehash of Cold War debates. To the contrary, nuclear strategy is back at the forefront of national security policy thanks to nuclear modernization efforts by Russia, China, and North Korea. These developments have been duly noted in the Defense Department’s new National Defense Strategy and Nuclear Posture Review, which have effectively put efforts toward long-term nuclear disarmament initiated by President Barack Obama (with the support of such stalwart Cold Warriors as Henry Kissinger, George Shultz, Sam Nunn, and Bill Perry) on the back shelf.
So Kroenig’s book arrives at an auspicious time for new analysis on nuclear strategy. The centerpiece of his argument is the “superiority-brinksmanship synthesis theory”: that nuclear superiority—a larger or otherwise more capable nuclear posture than a rival—increases a state’s power in crisis bargaining by means of increasing its resolve. This builds directly on the premise first established by Thomas Schelling that nuclear crises are “competitions in risk taking,” where the party most willing to run risks (that is, engage in brinksmanship) will prevail.
To make his case, Kroenig organizes the book in two parts, subtly tilting the analytic playing field in his direction with the subtitles “The advantages of nuclear advantages” and “The disadvantages of nuclear advantages?” He identifies four interrelated advantages: reducing the cost of nuclear war, increasing resolve in crisis, providing coercive bargaining leverage, and enhancing deterrence. He then critiques arguments about four ostensible disadvantages of U.S. nuclear superiority: increasing the likelihood of nuclear war, sparking arms races, exacerbating proliferation, and costing too much.
The book is the first in Oxford University Press’s “Bridging the Gap” series, aimed at improving the worthy but perennially difficult goal of better linking academic and policy experts in areas of international relations. In this context, the book is exemplary in several respects. First, it tackles a complex policy problem involving several related but competing objectives (such as deterrence, assurance, military effectiveness, stability, nonproliferation) without limiting its analysis to only one relevant policy variable. Second, it employs a variety of methods to interrogate its subjects, including statistical analysis, case studies, simulation, deductive reasoning, and reviews of the rich existing literature on nuclear strategy. Third, Kroenig gives substantial space and analytic attention to alternative theories that compete with his own. Fourth, as noted, he does not limit his case to explaining the benefits of nuclear superiority but devotes the second half of the book to rebutting arguments about the disadvantages of nuclear superiority. Together, these features make for a thorough, clear, and transparent analysis.
At the same time, Kroenig’s framing of his argument sets up what many policy analysts may view as a strawman. The notion that assured destruction should be the essence of U.S. nuclear strategy may be “a widespread and long-standing academic conventional wisdom,” as Kroenig argues. However, as he points out himself, this has seldom—if ever—been the sole rationale given among policymakers, who have touted substantial consideration for decades to counterforce strategies, damage limitation, and options for limited nuclear operations that diverge from an assured destruction strategy. Kroenig’s description of the conventional wisdom is a bit of a caricature: “Scholars argue that nuclear capabilities above and beyond a second-strike capability do not matter.” Some do, but many others cited in Kroenig’s bibliography (such as Richard Betts, Paul Bracken, Frank Gavin, Brendan Green, Keir Leiber, Austin Long, Daryl Press, and Philip Zelikow) do not.
But what about the overall case for pursuing strategic superiority? Kroenig builds a formidable argument that should capture the attention of both academic and policy specialists in the field. But caution is warranted, as the evidence presented is rather more ambiguous than his confident claims suggest.
One of the pillars of the analysis is the notion that nuclear superiority lowers a state’s expected costs in a catastrophic nuclear war. Key to this is Kroenig’s assessment that U.S. policymakers in a crisis would see a meaningful difference between war outcomes of, say, 50 million and 70 million American dead. While no one would argue that the 20 million difference is irrelevant, there are three major problems with this argument.
First, the nuclear war scenarios he simulates are only all-out, arsenal-emptying exchanges on the combatants’ homelands. Most would agree that these are the least likely of nuclear war scenarios today, and even during much of the Cold War. Instead, scenarios that have preoccupied strategists recently are limited regional conflicts and inadvertent escalation in contexts of U.S. extended deterrence, perhaps even without any targeting of the combatants’ homelands. Kroenig acknowledges this point in the final pages of the book but essentially argues that his logic extends to limited nuclear war since the risk of wider escalation is always present.
Second, the most relevant question with respect to how leaders would think about costs and benefits of nuclear war is not whether they are indifferent to between 50 and 70 million casualties. Leaving aside the fact that such estimates are wildly uncertain in any case, the key question is whether leaders might see the stakes in a plausible political conflict with another nuclear rival as being worth enduring 50 million casualties, but not 70 million. It is this logic that would link strategic superiority to greater risk propensity in a crisis, but this logic is harder to believe.
Of course, whether leaders think this way is an empirical question. Kroenig’s case would have been bolstered by even a single example of a U.S. leader articulating this kind of logic, but none is presented. In his case studies of nuclear crises (chapter 3), he does offer useful examples of leaders identifying nuclear superiority as a consideration in their behavior during crises. But this falls well short of demonstrating that the cost-benefit logic he lays out is actually relevant to decisionmaking in nuclear states.
The book presents several statistical analyses on the value of nuclear weapons for coercion. These questions are especially important to policy debates, since the locus of current concern over nuclear war risks is in regional conflicts between nuclear powers or their proxies in places like Korea, Taiwan, and Eastern Europe. In such scenarios, revisionist powers may hope that their nuclear weapons could serve as a shield for limited conventional aggression. So the book’s statistical analysis on coercion is welcome and valuable. However, Kroenig claims more power for it than is warranted. He translates 20 “nuclear crises” where “victories” were evenly split between states with and without nuclear superiority into 52 observations for regression analysis. That analysis shows nuclear superiority as the most important determinant of crisis victory. Kroenig clearly explains the methodology that enables such a counterintuitive result, but his interpretation of the results as a “powerful relationship” between superiority and crisis outcomes and as “strong empirical support” for his arguments is a stretch. Readers interested in this should review the rival arguments of scholars Todd Sechser and Matthew Fuhrmann, who come to different conclusions in their book Nuclear Weapons and Coercive Diplomacy (Cambridge University Press, 2017).
Importantly, Kroenig rejects traditional arguments that strategic superiority can be destabilizing by generating incentives for preemptive first strikes. This ultimately leads him to conclude that an “ideal nuclear posture” is one that would render the United States “as invulnerable as possible to nuclear attack from its three nuclear-armed rivals . . . while simultaneously maximizing adversary vulnerability to nuclear war.” He leaves unsaid that such a policy applied to current U.S.-Russia relations would be a major departure not only from the arguments of the academics he criticizes, but also from decades of U.S. strategy whose logic he purports to explain (not to mention from U.S. obligations under current arms control regimes).
Perhaps the most significant issue with deriving policy implications from the analysis is Kroenig’s definition of superiority itself. In the book’s foundational quantitative analysis, superiority is defined by the difference between two nuclear states’ numbers of warheads. Kroenig acknowledges that this is an imperfect measure but downplays the limitation’s importance. A true accounting of superiority would address not only warhead counts but also a wide variety of capabilities such as command and control, delivery vehicles, readiness posture, defenses, and the like. In a nuclear peer relationship, as between the United States and Russia, policymakers will never really think about superiority in the way that Kroenig measures it. And in other key relationships, like between the United States and China, capability disparities are so large that superiority as a policy choice is remote from the most important drivers of nuclear strategy.
By the same token, the rationales underpinning the expansion or modernization priorities of today’s major nuclear powers are not tied to the aggregate nuclear balance among countries. Instead, they are efforts to enhance deterrence and resilience under specific, stressful scenarios where nuclear attack could conceivably be contemplated.
In this sense, the book’s title works better as a riposte to Jervis than as a policy guide. The “logic of American nuclear strategy,” after all, has been shaped by many considerations, with “superiority” being just one among them. And readers should be particularly hesitant to accept Kroenig’s implication that a U.S. arsenal far larger than Russia’s would be an unambiguous and unvarnished benefit to U.S. national security. Nevertheless, Kroenig certainly succeeds in showing how and why strategic superiority can matter, and his analysis will undoubtedly earn a prominent place in both academic and policy debates in the years ahead. JFQ