Russian sailors line a deck of the nuclear ballistic missile submarine in Saint Petersburg, July 2021
Russian sailors line a deck of the nuclear ballistic missile submarine in Saint Petersburg, July 2021
Sputnik /Aleksey Nikolskyi / Kremlin via Reuters

In recent months, American policymakers have more than once found themselves contending with a danger that had for decades seemed consigned to the dustbin of Cold War history: the prospect of war with a nuclear-armed adversary. A clash with China over Taiwan has seemed more and more possible as U.S. and Chinese aircraft and vessels increase their presence in the Taiwan Strait. And in the past weeks, the Ukraine crisis has generated a risk of escalation with Russia that has sidelined all other foreign policy issues.

Such challenges, coming in the wake of a years-long refocusing of U.S. defense strategy on competition with China and Russia, have put questions of deterrence back at the heart of U.S. strategic considerations. In the coming weeks and months, the administration of U.S. President Joe Biden is due to roll out its National Security Strategy, National Defense Strategy, and Nuclear Posture Review. Deterrence—especially nuclear deterrence—is likely to be a centerpiece of all three. Secretary of Defense Lloyd Austin speaks of “integrated deterrence,” which combines the full range of U.S. military capabilities (nuclear, conventional, space, and cyberspace) with diplomatic and economic tools. Other analysts argue that deterrence depends on strong military forces capable of defending against any aggression—“deterrence by denial”—or on imposing costs on an adversary.

As this new generation of analysts and top national security officials grapples with updating deterrence for a time that may be even more challenging than the Cold War (given changes in technology, declining U.S. economic might, and a greater number of nuclear powers), they would do well to consider the work of Robert Powell, who served as Robson Professor of Political Science at the University of California, Berkeley, until his death in December. An economist by training, Powell was responsible for groundbreaking research on game theory that shed light on aspects of deterrence often overlooked in today’s discourse. Policymakers and academia have yet to combine efforts to the degree that was the case in the Cold War.

Most important, Powell explained how the risk of escalation is a fundamental of deterrence. The unavoidable chance of things sliding out of control can dominate the behavior of nuclear powers in crisis and in war, possibly more so than the balance of military or economic strength. In this situation, Powell noted how the balance of interests—which side places greater value in the stakes at play—matters for which side is better able to deter. The side with greater interests at stake can be more willing to face the risk of escalation. They simply care more. For U.S. policymakers today, that insight underscores the inevitable disadvantage they face in efforts to deter China and Russia from acting on what those countries consider critical interests, such as Taiwan and Ukraine. A hard reality is that the United States might be better off confronting Russia and China closer to home, where the United States has greater national interests at stake, where it is more willing to run the risk of escalation.

GREATER INTERESTS, GREATER RISK TOLERANCE

Although most contemporary military officers and defense and intelligence analysts have been taught the rudiments of game theory, they generally lack knowledge of the more sophisticated methods that since the 1960s can help them make sound strategic decisions while accounting for such factors as dynamic interactions, multiple players, differing risk perceptions, and incomplete information. John Nash, Thomas Schelling, John Harsanyi, Reinhard Selten, and Roger Myerson all received Nobel Prizes for discoveries involving new applications of game theory. Powell was among the first to apply game theory to international relations. His 1990 book, Nuclear Deterrence Theory: The Search for Credibility, explores brinkmanship, cost imposition, counterforce, off-ramps, and the risk of surprise attack—all subjects that remain relevant today. His 1999 book, In the Shadow of Power: States and Strategies in International Politics, formally models fundamental international relations problems, examining diplomatic bargains, balancing domestic and defense spending, and shifts in the distribution of power and military technology. Powell refined the results of these experiments in a series of articles published between 2004 and 2020. In 2015, he produced one of the first formal models capable of integrating the dynamics of a conventional war with the dynamics of nuclear escalation.

Risk and the balance of interests were recurrent themes in Powell’s work. Powell questioned the degree to which conventional military capabilities would remain relevant in a modern war between adversaries with recourse to nuclear weapons. The United States might successfully repel a Chinese assault on Taiwan, for example, yet that would not prevent China from escalating with nuclear strikes.

Powell returned repeatedly to the concept of brinkmanship as defined by the pioneering American game theorist Thomas Schelling. Brinkmanship, Schelling wrote, “is a competition in risk-taking. It involves setting afoot an activity that may get out of hand, initiating a process that carries some risk of unintended disaster.” Powell was impressed by the notion that a war between states with nuclear second-strike capabilities would boil down to a competition in risk-taking. A state that highly values the stakes, he wrote in 2015, has “an incentive to adopt doctrines and deploy forces that make the use of force riskier and thus easier to transform a contest of military strength into a test of resolve.”

Powell’s models focused on determining not relative military strength but which side had the greater stake in the issue at hand. Although a state may be able to bluff an adversary into backing down by feigning a greater stake, the side that genuinely has the greatest stake will likely tolerate more risk and display more endurance. This logic is apparent in the infamous veiled threat contained in Chinese Lieutenant General Xiong Guangkai’s remark to U.S. Assistant Secretary of Defense Chas Freeman during the Taiwan Strait crisis of 1996: “Americans care more about Los Angeles than they do about Taiwan.”

The 2018 National Defense Strategy asserted that “the surest way to prevent war is to be prepared to win one.” Powell’s work counsels a very different approach to preventing war. Deterrence, he concluded, is best achieved by credibly signaling that any conflict would carry a higher risk of escalation than the adversary is willing to bear.

The implication is that no new defense strategy can be complete without the risk of escalation front and center as fundamental to deterrence. China and Russia must recognize that the United States is credibly committed to bearing the risk of escalation if they conduct aggression. As part of the Biden administration's ongoing drive to fortify alliances battered by COVID-19 and former U.S. President Donald Trump, the United States could reinforce the message by making it clear that willingness to bear risk applies to U.S. allies, too. Strengthening U.S. alliances raises the risks for Russia and China because alliances cannot be broken without incurring significant domestic and international political costs. A so-called tripwire strategy that positioned U.S. forces in places vulnerable to Chinese or Russian aggression so as to make a clash with the United States inevitable could help demonstrate commitment. Powell stressed that slowly ratcheting up risk via methods such as selective sanctions, discriminatory nonkinetic antisatellite capabilities, and precision conventional strikes, could also be an effective deterrent. This more gradual approach, he argued, was far safer than the sorts of strategies—full-scale blockades, indiscriminate destruction of satellites, or all-out counteroffensives—that effectively forced presidents toward the brink.

THE IMPORTANCE OF SELF-INTERROGATION

Perhaps most important, Powell’s work compels policymakers to thoroughly interrogate American interests and goals to determine whether the United States truly has more at stake than its adversaries. Against a determined adversary, the risk of brinkmanship runs high. Brinkmanship that requires placing long-range strike systems in Ukraine or Taiwan, as Soviet Premier Nikita Khrushchev did in Cuba, would seem manifestly dangerous. In such cases, the solution is not to jettison brinkmanship and instead build more conventional forces. The solution, Powell would likely counsel, is to scale back policy goals and seek to cement one’s defensive and risk-taking posture for more plausibly vital interests.

The United States can work to strengthen deterrence by reinforcing alliances, posturing forces as tripwires, and identifying multiple options to ratchet up risk. None of those steps, however, can alter an underlying imbalance of interests. The Biden administration’s new defense strategy could benefit most from a thorough analysis of those interests and clear-eyed thinking about where U.S. interests really lie. Deterrence should be more credible if the United States does not try to confront Russia over Ukraine and the Black Sea. Confronting China over Taiwan is a tougher question because of the island’s strategic position. Nevertheless, there should be a sober acceptance that U.S. willingness to confront China would surely be more credible over Japan, South Korea, or the Philippines. A strategy that inadvertently commits the United States to a greater risk of nuclear war than its interests bear benefits no one.

The future that is coming into view differs from the bipolar competition of the Cold War. Even after his death, Powell’s work will continue to offer critical insights as we seek to safely navigate this future. Yet few scholars today can match Powell’s aptitude for combining theory, math, and strategy. As we again confront questions of nuclear and conventional deterrence, in a new and rapidly developing technological context, his guidance will be sorely missed.

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