Analysis & Opinions - Negotiation Journal

Preventing Nuclear War: Schelling's Strategies

| July 23, 2018

I am indebted to Tom Schelling in many more ways than I can ever say. I had the great fortune to know him as an author, teacher, mentor, senior colleague, and, when I became dean of what was to become the Harvard Kennedy School, as an employee – at least that is what it said on the organization chart. Most valuably, he was a friend. In this essay, I will focus on Thomas Schelling, the thinker and author whose writings remain for all of us to read and re-read today and whose insights continue to clarify current challenges.

If forced to choose just one word to characterize the mind of Tom Schelling, I would say: luminous. If given several words: luminous, original, fearless, and elegant.

Among the many issues Tom illuminated, this essay will focus on the one he cared about most, the defining challenge of his lifetime: finding ways to survive in a world in which humans hold the capability to destroy their own species. The possibility that leaders could make choices that would produce a war killing literally all of us is so horrific as to be virtually unthinkable. It is, nonetheless, a brute fact. As Winston Churchill put it: “without having improved appreciably in virtue or enjoying wiser guidance, mankind has gotten into its hands for the first time the tools by which it can unfailingly accomplish its own extermination” (Churchill 2009: xxvi).

Many people today prefer to imagine that somehow all of this went away when the Soviet Union disappeared twenty-five years ago last December. In truth, the gruesome realities Tom confronted have not gone anywhere. Today, President Donald J. Trump has in his hands the power to destroy every living creature on Planet Earth. And he is not alone – so too does Russian President Vladimir Putin. 

As Tom would often put it: so what do you make of that? Of the many things he made of it, let me highlight three: the assertion of an essential role for independent, university-based civilians in shaping strategy for managing the threat and use of nuclear weapons; the recognition that superpower nuclear arsenals make war between superpowers suicidal; and the invention of “arms control,” not as disarmament, but as a way of constraining risks that accidents, miscalculations, and misunderstandings could trigger this doomsday machine.

After the United States dropped the first bombs on Hiroshima and Nagasaki, most policymakers saw these weapons as simply the next generation of bombs that offered more bang for their buck. As U.S. President Eisenhower once said, “I see no reason why they shouldn’t be used just exactly as you would use a bullet or anything else” (New York Times 1955: 1). Tom was a key member of the first-generation of civilian strategists who demonstrated that they could think about these issues at least as clearly as military officials. As another of their members, Alain Enthoven, put it bluntly: “General, I have fought just as many nuclear wars as you have” (Kaplan 1983: 254). In his 1946 book, The Absolute Weapon: Atomic Power and World Order, Bernard Brodie, one of the founding members of this group, argued that: “thus far the chief purpose of our military establishment has been to win wars. From now on its chief purpose must be to avert them” (Brodie 1946: 76). That would require a revolution in relations among nuclear-armed states. 

To address this challenge, Schelling developed a theory of what he called the “strategy of conflict.” The foundation of the strategy of conflict was the assumption of “rational behavior.” As he explained, this means “not just of intelligent behavior, but of behavior motivated by a conscious calculation of advantages, a calculation that in turn is based on an explicit and internally consistent value system” (Schelling 1960: 4).

This assumption allowed him and his fellow strategists to employ a methodology he labeled “vicarious problem solving.” As he said, “you can sit in your armchair and try to predict how people will behave by asking how you would behave if you had your wits about you. You get, free of charge, a lot of vicarious, empirical behavior” (Allison and Zelikow 1999: 49). On this foundation, Schelling developed dozens of insights that he presented first in The Strategy of Conflict (1960), followed by Strategy and Arms Control (1961) and Arms and Influence (1966). He became a leading light in the first generation of nuclear “wise men and women” that included Brodie, Herman Kahn, William Kaufman, Henry Kissinger, Albert Wohlstetter, and Roberta Wohlstetter, who, from independent bases at the RAND Corporation, Harvard University, and the Massachusetts Institute of Technology, engaged American military and political leaders in “thinking the unthinkable.”

Schelling’s conception of strategy provided the intellectual foundation for my own doctoral thesis, which became Essence of Decision (Allison 1971). That book articulated Model I, the Rational Actor Model, which helped launch the rational choice school in political science. Tom subsequently noted: “The rational choice movement in political science mostly extends and formalizes the Rational Actor Model” (Allison and Zelikow 1999: back cover) But by developing Models II and III, the Organizational Process and Governmental Politics Models, and showing how the causal factors they highlight could lead to wars no rational individual would choose, Essence of Decision also contributed to a second generation of thinking about the use, and prevention of the use, of the ultimate weapon (Allison and Zelikow 1999). 

What is the most significant consequence of nuclear arsenals after they become robust enough to survive a first strike by an adversary and still destroy that adversary in response? Albert Einstein’s one line answer declared: “The unleashed power of the atom has changed everything save our modes of thinking” (Lapp 1964: 54). Tom was one of only a handful of seminal thinkerswho actually began to change that thinking. 

His central insight was this: the existence of superpower nuclear arsenals transforms the relationship between deadly adversaries. In game theory terms, theirs was no longer a “zero sum” game. Instead it was a mixed-motive or interdependent game in which “conflict is mixed with mutual dependence,” creating a “precarious partnership” (Schelling 1960: 15, 83).  

Tom also made analysts wrestle with game theory’s “chicken” dilemma. Not only are confrontations between nuclear superpowers, such as the 1962 Cuban Missile Crisis, a version of “chicken.” Even less comforting, he insisted, was the fact that in this contest, no dominant strategy exists. To make this point more intuitive, he would challenge students, readers, and policymakers to think about the game memorialized in movies like Rebel Without a Cause. In one version of the game, two testosterone-driven young men would each put the left wheel of his car on the center lane of a highway and drive toward each other from opposite directions at full speed. The driver who flinched and turned away was declared the chicken. The winner was declared the champion and got the girl. If neither turned away, they crashed and both died. 

Tom spent endless hours and many concise and tightly-argued pages helping explain how under such conditions it is possible to manage competition, preserve one’s vital interests, and still survive. His insights were tested during the missile crisis of October 1962, when Soviet Premier Nikita Khrushchev put his left wheel on a line driving recklessly toward a point at which he would have placed nuclear-tipped missiles in Cuba capable of attacking the American homeland. President John F. Kennedy insisted he would never allow this to happen. To prevent it, he chose to confront Khrushchev directly. In effect, he put the left wheel of the United States on the center lane Khrushchev had chosen and stepped on the gas. Over thirteen intense days, the two accelerated toward a colossal collision. As Kennedy later said, he believed that the odds of the crisis ending in war with the Soviet Union were “between one-in-three and even.”

At the last moment, each had second thoughts – and together, they found an imaginative way to escape (Allison 2017: 234). Having survived the searing experience of existential nuclear danger, both came away changed human beings. For Kennedy, the enduring lesson of the Cuban Missile Crisis was: “Above all, while defending our own vital interests, nuclear powers must avert confrontations that force an adversary to choose between a humiliating retreat and nuclear war” (Kennedy 1963). 

The crisis opened both their minds to a third and even more radical line of thinking that Tom had been exploring: how to constrain and ultimately avoid repeat plays of a game that was bound to end in disaster. In the months that followed the missile crisis, the Kennedy Administration sponsored a surge of initiatives that reduced the risk of accidents, unauthorized launches, misperceptions, and misunderstandings. These included establishing the telephone “hotline” between the White House and the Kremlin in Moscow, signing the Limited Nuclear Test Ban Treaty, placing electronic locks on warheads (Permissive Action Links, or PALs), and beginning negotiations that in time established the Nonproliferation Treaty. The conceptual foundation for deadly adversaries to cooperate in finding ways to nonetheless constrain their competition was largely laid by Tom.  

It is worth considering what this luminous mind might make of the intensifying competition between a rising China and the ruling United States today – and its most dangerous current expression on the Korean Peninsula (Allison 2017). In Tom’s terms, North Korea’s leader Kim Jong-un has put his left wheel on a centerline and has been driving relentlessly toward a point at which he will be able to attack San Francisco and Los Angeles with nuclear warheads. Like President Kennedy before him, President Trump has declared unambiguously that this will never happen. To prevent it, he has demonstrably taken his seat behind America’s military machine, put its left wheel on the centerline Kim Jong-un chose, and is now accelerating toward an impending collision. 

In a phrase, we are witnessing a Cuban Missile Crisis in slow motion. But in this case, the American President is playing nuclear chicken not with the leader of the Soviet Union, but with the erratic Kim Jong-un. To extend the metaphor, in this case, South Korea, Japan, and even China find themselves involuntary passengers in the backseats of the cars driven by Trump and Kim, terrified by the possibility that a crash could mean North Korean nuclear weapons exploding on or near their territory.  

Recognizing that when Presidents Bill Clinton, George W. Bush, and Barack Obama found themselves playing chicken with North Korea, each chose to swerve to avoid war, Trump has focused instead on China’s leader Xi Jinping, who controls the oil lifeline that powers Kim’s nuclear and missile programs. Trump is thus now playing a version of chicken with Xi. As he told Xi bluntly before the Mar-a-Lago summit in April 2017: You solve this problem, or I will, and you won’t like the way I do it. Then, just after he served Xi and his wife chocolate cake at the end of the opening dinner, he excused himself, went to an adjacent room, and announced that the US had just launched fifty-nine cruise missiles against Syria – to both punish Syrian President Bashar al-Assad for his use of chemical weapons on Syrian civilians – and also presumably to underline how he might solve the North Korean problem (Allison 2017). 

To stop North Korea’s nuclear advance, can Trump order similar strikes on North Korean intercontinental ballistic missile (ICBM) launch pads? Of course. The question, however, is how Kim Jong-un will respond. And if the U.S. intelligence community’s expectation that he will retaliate with artillery attacks on Seoul is correct, and if the U.S. and South Korea respond to that by suppressing weapons that could attack the South Korean capital, will this mean a second Korean War? In such a war with a nuclear-armed North Korea, will Kim Jong-un launch warheads against South Korea or Japan? Will China follow in the footsteps of its leader Mao Tse-tung who in 1950 entered the Korean War and beat American forces back to the 38th Parallel where the war began?

Testifying about these prospects, Secretary of Defense Jim Mattis has repeatedly used one word: “catastrophic.” In the first Korean War, tens of thousands of Americans, hundreds of thousands of Chinese, and millions of Koreans were killed – most by American and Chinese forces. A second Korean War could claim millions of victims. 

So: if Xi Jinping fails to stop Kim Jong-un’s nuclear advance as it approaches the point at which Kim will have a capability to attack American cities with nuclear weapons, will Trump keep his left wheel on the line and crash into the North Korean vehicle, leading to a second Korean War? It seems incredible. It is. But that is the road on which both are now traveling.  

Recognizing the ugliness of the options before them, will Trump and Xi find a creative way to avoid a collision, as Kennedy and Khrushchev did half a century ago?

Will Xi do everything he can, including squeezing North Korea’s oil lifeline, to force Kim to the table? In return for a halt to Kim’s nuclear and missile tests, would Trump be willing to make adjustments to U.S. military exercises that, while uncomfortable, would not compromise anything vital? 

One is tempted to ask: where is Tom now that we really need him? As he watches this unfold, I'm sure he would have at least a dozen pointers – from reminders about the necessity for brinksmanship if something genuinely unacceptable is otherwise going to happen; to the rationality of seeming irrational; the credibility of an otherwise incredible threat that leaves something to chance; and the necessity to focus on the target in bargaining – which is not destruction of physical objects but impact on the mind of the adversary. And Tom would likely remind us that, because the consequences of a collision are so disastrous for both parties, “chicken” is also a “somewhat collaborative” game. 

To avoid a deadly collision without jeopardizing reputation, Tom suggested that “the players may try to signal each other to try to coordinate on a tie; if each can swerve a little, indicating that he will swerve a little more if the other does too, and if their speeds are not too great to allow some bargaining, they may manage to turn at approximately the same time, neither being proved chicken” (Schelling 1966: 119). Whether Trump and Kim could agree on a mutual compromise along the lines suggested above, only time will tell.  

We miss Tom dearly – but fortunately we can still read his books and learn. 


Allison, G.. 1971. Essence of decision: Explaining the Cuban Missile Crisis. Boston: Little, Brown and Company. 

Allison, G. and P. Zelikow. 1999. Essence of decision: Explaining the Cuban Missile Crisis (2nd Edition). New York: Addison Wesley Longman. 

Allison, G.. 2017. Destined for war: Can America and China escape Thucydides’s trap? Boston: Houghton Mifflin Harcourt.

Allison, G.. 2017. “Will Trump and Xi ‘Solve’ North Korea?” Politico. November 8, 2017. Available at, B. 1946. The absolute weapon: Atomic power and world order. New York: Harcourt Brace.

Churchill, W. 2009. Shall we all commit suicide? In Thoughts and adventures: Churchill reflects on spies, cartoons, flying, and the future. Edited by James W. Muller. Wilmington, Delaware: ISI Books.

Kaplan, F. 1983. The wizards of Armageddon. Stanford, CA: Stanford University Press.

Kennedy, J. F. 1963. Commencement address at American University. June 10. Available at 

Lapp, E. 1964. The Einstein letter that started it all.” New York Times. August 2. Available at…;

New York Times staff. 1955. President says atom bomb would be used like “bullet”; Eisenhower talks of atom “bullet.” New York Times. March 17: 1, 4. Available at….

Schelling, T. C. 1960. The strategy of conflict. Cambridge, MA: Harvard University Press.

Schelling, T. C. 1966. Arms and influence. New Haven: Yale University Press.

For more information on this publication: Belfer Communications Office
For Academic Citation: Allison, Graham.“Preventing Nuclear War: Schelling's Strategies.” Negotiation Journal, July 23, 2018.