The new psychology of nuclear brinkmanship (originally released February 2023)

Trending Globally will be back with all new episodes soon, but in the meantime we’re rereleasing some of our favorite episodes from 2023. We hope you enjoy – and have a great start to 2024!


The beginning of 2023 saw a disturbing milestone: the Bulletin of the Atomic Scientists moved the ‘Doomsday Clock’ forward to 90 seconds to midnight – the closest it’s been to ‘Doomsday’ since the clock was established in 1947. 

But what would it take for a nuclear weapon to actually be used in the world today? And if one was used, how would the rest of the world respond? 

In this episode (originally released in February 2023), the second in our limited series on the theory, policies, and practice of conflict escalation, you’ll hear from two experts rethinking how nuclear threats are understood and modeled. 

Rose McDermott is a professor of International Affairs at the Watson Institute, and Reid Pauly is an assistant professor of Nuclear Security and Policy at Watson. Their paper “Decision-making Under Pressure: The Mechanisms and Psychology of Nuclear Brinkmanship” is the lead article in the current issue of International Security. In it, they reframe one of the most fundamental theories for understanding nuclear risks: nuclear “brinkmanship.” They highlight why conventional models of brinkmanship fail to fully explain how a nuclear crisis might unfold and explore what interventions are needed to prevent one from starting. 

Read Rose and Reid’s paper, “Decision-making Under Pressure: The Mechanisms and Psychology of Nuclear Brinkmanship.”

Listen to the first episode in our limited series, “Escalation,” with Lyle Goldstein. 

Learn more about the Watson Institute’s other podcasts. 


DAN RICHARDS: Hey there, listeners. We'll be back soon with some all new episodes of Trending Globally. But in the meantime, we're rereleasing some of our favorite episodes from this past year. This one explores an important, and to be honest, terrifying topic in the world of international relations. And it is sadly just as relevant as when it was released last year. I hope you enjoy.


From the Watson Institute for International and Public Affairs at Brown University, this is Trending Globally. I'm Dan Richards. Well, this happened.

MALE REPORTER: The world's Doomsday Clock has been moved forward.

FEMALE REPORTER: The Bulletin of the Atomic Scientists is warning the world is closer to global annihilation than ever before in part due to Russia's invasion of Ukraine. Since Nineteen Forty-Seven, the Bulletin has maintained a Doomsday Clock to illustrate how close humanity is to the end of the world.

The members of the Science and Security Board moved the hands of the Doomsday Clock forward, the closest it has ever been to midnight. It is now 90 seconds to midnight.


DAN RICHARDS: It's not hard to see why the clock moved forward. But what would it actually take for nuclear weapons to be used in the world today? And how would the rest of the world respond?

On this episode, our second in a series on the theory, policies, and practices of escalation, you'll hear from two experts who are rethinking the traditional ways that politicians, government officials, and scholars have thought about nuclear conflict.

They're doing so by bringing a more nuanced view of human psychology and of our security infrastructure into the models that people use to predict and hopefully prevent nuclear conflict. Because while sometimes security strategy can seem like chess pieces on a board, often it might more accurately be thought of as something like group therapy.

ROSE MCDERMOTT: We all know from the mirror of introspection, right, like we've all had experiences where our emotions get the better of us. And we somehow think that doesn't happen to leaders. We shouldn't assume that leaders are better than the regular person in being able to control their emotions in times of conflict and threat and risk and crisis.

DAN RICHARDS: And perhaps it's especially true at those moments when the stakes couldn't be higher.

REID PAULY: War is hell and war in the nuclear age is civilization-destroying. In Nineteen Forty-Five, we invented the ability to destroy ourselves, and we have so far managed to avoid nuclear Armageddon. We are here again, managing the risks of nuclear weapons.

DAN RICHARDS: That was Rose McDermott and Reed Polly. Reid is an assistant professor of Nuclear Security and Policy at Watson. And Rose is a professor of international affairs, who you've probably heard on the show before. Together, they're reframing one of the most fundamental theories for understanding nuclear risk, what we call nuclear brinkmanship.

On this episode, Reid and Rose explain what traditional understanding of nuclear brinkmanship gets wrong about how nuclear powers actually behave in conflict. Because if we want to stop a nuclear war from happening, we need a better understanding of why one would start in the first place.


Before getting into Reid and Rose's recent paper on the topic, which was the lead article in the most recent issue of International Security, we started with a definition of brinkmanship and its meaning in the nuclear age. While it's probably a phrase you're familiar with, can you really define it? Here's Reid.

REID PAULY: Brinkmanship, you should think about the word brink at the beginning of it, right? This is the manipulation of the risk of mutual disaster for the purposes of coercion. So there are some brink that you and I both would rather not go down, but I'm going to manipulate the chances of us going over that brink in order to get you to do what I want you to do.

DAN RICHARDS: And by manipulate, you mean kind of increase the chances.

REID PAULY: Yes, exactly.

DAN RICHARDS: Brinkmanship in one form or another has existed for a long time. Countries have long risked and threatened war with other countries to try and get what they want out of them.

REID PAULY: If I can manipulate more risk and signal to you that I'm more resolved by my appetite to take that risk than you are, then you should give in, and I should win.

DAN RICHARDS: But the calculations behind these risks fundamentally changed with the creation of nuclear weapons. The brink adversaries now risked falling over wasn't just a war, it was the potential destruction of all of humanity. Nuclear weapons, the Cold War, and events like the Cuban Missile Crisis forced people to rethink how conflict, risks, and coercion would work in this new world.

One of the most influential theorists on the topic was an economist and game theorist named Thomas Schelling. We're going to talk about him a lot in this episode. And one of his core insights into understanding brinkmanship in the nuclear age was this.

REID PAULY: If I have nuclear weapons, it is difficult for me to credibly threaten to use them.

DAN RICHARDS: Why is that?

REID PAULY: It's difficult because if I threaten to use them against another country that has nuclear weapons, if I use nuclear weapons against them, they will use them against me. And so we will both go into the abyss off the brink as it were.

For other reasons, it's also difficult to credibly threaten to use nuclear weapons against anyone. Sometimes we talk about there being a taboo against the use of nuclear weapons. No one has used nuclear weapons in war since Nineteen Forty-Five. And so breaking that barrier is something that is imbued with significance in international politics.

It's also judged to be by many I think quite rightly to be highly immoral, something that a weapon that is very difficult to use discriminately. Many innocent people would be assumed to die if there was ever a use of nuclear weapons. And so immoral threats are actually less credible because you have to convince the other side that you're capable and resolved enough and willing to break that taboo to do something so immoral as use nuclear weapons.

And so in all circumstances, states that have nuclear weapons and leaders that have them at their disposal, struggle with what they actually mean for leverage. How can I use them to my advantage.

DAN RICHARDS: Right. If no one takes it as credible, then it's not that useful.

REID PAULY: Exactly right. Exactly right. So one of the things that Schelling noted is that it's a lot less about what I can actually do to you and a lot more about what I am willing to do to you, and whether I can make my threats to punish you credible.

DAN RICHARDS: According to Schelling's model of nuclear brinkmanship, no rational person would ever use a nuclear weapon for all of these reasons. So how then could a person or nation ever make threats of nuclear force that are credible? Schelling's answer to this conundrum-- by intentionally and strategically introducing risk and chance into the escalation.

REID PAULY: What I do if I have nuclear weapons and I would like to use them to my coercive advantage against an adversary that also has nuclear weapons is instead of simply saying, I'm going to use my nuclear weapons against you unless you obey me. What we do is we manipulate the risk of mutual disaster.

DAN RICHARDS: Upping the risk of having things slide out of control somehow, like what people feared in moments like during the Cuban Missile Crisis. That is how a nuclear threat could be taken seriously. Schelling's iconic analogy for all of this--

REID PAULY: Two climbers chained together at the edge of a cliff.


So the two climbers, mountaineers, if you will, at the edge of a cliff are chained together. And the idea is that because of that chain that connects us both, one climber cannot say to the other that I threatened to push you off the cliff because that will doom us both.

So instead, while they could start to walk closer to the edge, they can start to dance. They can stand on one foot. And through all these actions, what the climber is doing is trying to signal that you and I both know that I will not push you. And you and I both know that I would rather not fall. But I am increasing the chances that I am going to fall and then that will lead to mutual disaster.

The theory then, as Schelling put it, was that whichever actor was willing to stomach more risk of disaster is the one that was going to win that crisis at the end of the day. If I can signal to you that I am more resolved by my appetite to take that risk than you are, then you should give in, and I should win.

DAN RICHARDS: So you might be asking, what's the equivalent of dancing on the edge of a cliff for a nuclear power? Well, maybe they would test a missile closer and closer to another country's territory. Maybe they would cross what some other country has described as a red line.

Maybe leaders claim that there's a chain of command in their government, such that in some point in an escalation, the decision whether or not to use a nuclear weapon is just taken out of their hands. No one will jump off the cliff, but people will dance right up to it. And if someone falls, we'd all fall very quickly.


So those are some of the key points of the most traditional model of brinkmanship, but there are a few problems with it according to Reid and Rose. We'll get into all the different sides of it, but they can kind of all be summed up as part of one bigger problem.

REID PAULY: In the original definition from Schelling, that really has continued and has been accepted in the field as the logic of how brinkmanship works, is his assumption that in order for it to work, you have to take the humans out of the situation.

DAN RICHARDS: But whether we're talking about why people make threats, how people respond to threats, or just how groups of people work together, humans in all their messiness and complexity cannot be removed from how we think about nuclear brinkmanship.

Reid and Rose are here to help bring humans back into how we think about nuclear brinkmanship. And in the process, they're making a model that more accurately reflects how a nuclear world operates.

The first thing they take issue with in the traditional model, the very idea of a, quote, "rational human" and what they would or wouldn't do. Thomas Schelling was an economist, remember. And as Rose puts it--

ROSE MCDERMOTT: Economic definitions of rationality aren't the only way to think about what's rational behavior is, right? So in the traditional economic explanation, the idea is that rationality is where you consider various options, and you pick the option that maximizes the probability of obtaining the thing that you value the most, right, or at least that your costs are less than your benefits or potential benefits.

And so part of the idea that Reid and I were trying to put forward in this article among others is that these notions of rationality depend on models of human nature that aren't accurate. That human nature, actually basic psychological instinct and processes, do not always operate in the way that conventional nuclear deterrence thinks that it should.

DAN RICHARDS: Advances in behavioral economics and psychology have taught us that humans can't be counted on to act, quote, "rationally all the time". Strong personal feelings, evolutionary and biological instincts and all sorts of other factors change how and why humans make the decisions they do. And it's not so much that we're not rational, as that--

ROSE MCDERMOTT: There's another way to think about rationality, where it's not about costs and benefits, especially in financial terms, but it's about things like survival. Your likelihood of being able to have children, who you raised to reproductive capacity, right? That's a very different kind of rationality and it may lead to a different kind of behavior that's about protecting your kin and so on.

DAN RICHARDS: And there's no reason to think that being in charge of a nuclear stockpile would remove that aspect of your humanity. This truth though, is kind of missing from Schelling's model, despite the fact that, quote, "irrational behavior" has been an aspect of war and conflict since, well, forever.

REID PAULY: Emotions are incredibly powerful, but they're especially powerful in conflict and crisis. We do cite throughout the paper are plenty of examples from the history of just conflict and conventional conflict at various points along the escalation ladder, but short of nuclear war, where leaders have made choices that are motivated by things like revenge.

So the common ones of famous examples come from very early, like in antiquity, when Alexander the Great was making choices about which cities to sack after they had surrendered to a siege versus not. Well, the ones he's sacked were the ones that resisted for long enough that they had become really frustrating to him.

And so none of that has to do with good strategic thinking, about when to use violence for material purposes or not. And everything to do with when you are frustrated and when emotions creep into your decision making and when they don't.

DAN RICHARDS: If nuclear weapons had existed back then, who knows what Alexander the Great might have done with them. Now, there's a challenge inherent to theorizing on nuclear war that Rose and Reed are quick to point out.

REID PAULY: Because we haven't seen a nuclear war since Nineteen Forty-Five. The paper is not full of examples of people using nuclear weapons out of revenge or for some emotional reason.

DAN RICHARDS: But there's one interesting example of human emotion entering into nuclear brinkmanship strategies that's pretty revealing.


ROSE MCDERMOTT: So the classic example of this is the Nixon madman theory. Richard Nixon, during the Vietnam War, wanting to get the North Vietnamese to surrender. And there's this great story of him walking on the beach in California with Bob Haldeman, and saying, Bob, you just tell the North Vietnamese that Nixon is crazy, that he's a madman, that he's got his finger on the nuclear button and he could push it in any minute, and they'll be at the peace table in a day or so.

The idea was that he was strategically using his reputation as "crazy" to get the other side to back down, that the idea that his emotions would get the better of him, that his anger, frustration, desire for revenge, whatever, would force the other side to capitulate.

DAN RICHARDS: It didn't really work, but in a way, that proves Rose and Reid's point.

ROSE MCDERMOTT: The other side did not believe that he was out of control.

DAN RICHARDS: Today, however, there are threats coming from a leader that, for all sorts of reasons, we are taking very seriously.

ROSE MCDERMOTT: A modern version of this is what's happening in the war in Ukraine. So you have a situation where Putin has nuclear weapons. If he didn't have nuclear weapons, NATO and the United States would have no problem going in and just eliminating the Russian army. But the reason we don't do that is because there's this notion that he might actually use nuclear weapons.

And we may look at that and say that's irrational. But then there's other analysts who say gee, he has this historical notion of himself as Peter the Great, as the person who's going to rebuild the Russian Empire, the historic Russian Empire, even before the Soviet Union. And that if he can't get that, his notion of himself in history, his legacy, his control over his regime are all at risk. And if he thinks that he's going to lose his control over the country, he has nothing else he cares about. That's the only thing that matters.

And so he might actually take that ultimate risk, even if it means killing all kinds of people, because he doesn't care about all those people. He doesn't care about his own soldiers, whatever argument you want to make, and so people can envision that he might actually do this. And that prevents us from doing all the things that we might otherwise do to defend Ukraine, to change the regime in Russia, to do all kinds of things that we might otherwise do.

DAN RICHARDS: So humans aren't rational always in the way that economists define it. That's the first big issue Reid and Rose take with the older model. The next is about how humans would behave once one side were to actually launch a nuclear weapon. To see what they're saying here, we have to go back briefly to that idea of risk and chance in brinkmanship.

Again, as Schelling saw it, the only way to credibly threaten a nuclear war, because we're all rational, is to take risks that could lead to well, basically, an accident. The climber won't rationally jump off the cliff, there's just too much to lose, but they could rationally take risks up their likelihood of falling off. So in other words.

REID PAULY: It's through accidents that you get nuclear war.

DAN RICHARDS: So then let's say an accident happens, a risk goes too far. What would come next according to the conventional wisdom on brinkmanship and nuclear security?

REID PAULY: The aftermath of accidents are assumed to have some automaticity, that they will be assumed to be the opening Salvo of a nuclear war. There is this assumption, sometimes explicit and often implicit, that agency starts to go out the window.

DAN RICHARDS: Once again, humans are removed from the picture.

REID PAULY: The question that Rose and I are interested in is, how do leaders respond to accidents?

DAN RICHARDS: Rose and Reid, for a number of reasons, don't think the chain of events would be quite so automatic. Leaders even in the aftermath of things like accidents can retain some agency. Maybe people in charge would exhibit surprising self-restraint, or perhaps those in charge of these decisions have implemented systems where they can't act alone and need to discuss options with advisors.

ROSE MCDERMOTT: What we do know is from a lot of work in psychology and judgment and decision making, you can put in procedures when there isn't a crisis. So that when there is a crisis, you can reduce the likelihood of these human errors and mistakes, even around emotion, occurring in a way that causes a negative outcome.

DAN RICHARDS: This understanding has actually been incorporated into nuclear security theories and practice for a long time, even if not quite so explicitly.

REID PAULY: There was a lot of work during the Cold War thinking about which weapon systems to ban, which weapon systems to invest in, which weapon systems to negotiate away, in an attempt to reduce the risk of escalation. And especially to stabilize crises, so that in a crisis with the Soviet Union, that we would try and minimize the extent to which each side would have an itchy trigger finger and need to go first. So that can lead to things like not firing a missile from a submarine on a depressed trajectory.

Meaning that there would be that many more minutes before the missile would arrive, such that leaders would have more time to make decisions, crucially about things like, is this actually a missile that's coming in my direction or do we have time to wait and see whether this is a computer chip that's malfunctioning?

Schelling wrote about this as the problem of haste. In every crisis is a problem of haste. You have to make decisions quickly. And when time is short, people tend to make less rational decisions. So the key arms control question is if you're worried about crisis stability.

If you've bought yourself some extra time with a more traditional arms control approach, like banning a certain weapon system, banning certain flight trajectories, whatnot, then the question is, OK, well you better also have something in place that's going to force leaders into thinking carefully about their approach with that extra time. Maybe it could lead to some stemming of emotional decision making in that moment.

DAN RICHARDS: Former Defense Secretary Bill Perry along with many others have put forward different ideas about how to do this.

ROSE MCDERMOTT: So that control of nuclear weapons is not in the hands of one man, meaning the president. That it has to include maybe even a troika, the Secretary of Defense, the secretary of state, whoever it is that you decide. And I think that that, at least, we can't control other countries. But in the American context, I think that that's a very important initiative. He's been standard bearer of that. And I think that it's something that those who are interested in re-instantiating arms control should also be interested in pushing forward.

DAN RICHARDS: This revision that Reid and Rose offer to traditional theories of brinkmanship, it alters the hikers on a cliff analogy. It's no longer one quick jump into the abyss, it's more like there are a series of ledges you can fall down. Each one hurts and ultimately, they might kill you. But crucially, there are multiple points for the climbers to reevaluate if they want to go up to the brink of the next one.

REID PAULY: And so by that mechanism, you can still see conflicts progress and end up being resolved through brinkmanship strategies even when leaders remain in control of their nuclear forces.

DAN RICHARDS: You might find this fact slightly reassuring. Unfortunately, the world as it is lacks many of the checks and balances that would actually slow down nuclear conflicts. Even in the United States.

REID PAULY: This is one of the things that when I talk to my students in a class called The Politics of Nuclear Weapons, that they do not believe at first. Which is that the President of the United States can start the greatest war, most destructive war known to humankind, without anybody else approving.

The president has the "nuclear football". The briefcase that follows him around in the event of a crisis, the idea is to try and make the threat of retaliation credible. So at a moment's notice. The president can open the briefcase, ask the Marine to come over and open the briefcase and decide to use nuclear weapons.

Officially, it only takes the president's order to do that. Now, the theory, the hope is that there would be plenty of other people in the room trying to advise the president about whether or not that's a good idea. And unfortunately, in the United States, we don't have as a system that can at least force the conversation to be had between advisors in a crisis moment.

ROSE MCDERMOTT: What's interesting in the United States case is it's not that if somebody else was in the room with the president they'd stop him. Where it might get stopped is the guy in the silo with the key. Because the American military does have a very strong tradition of civilian control of the military. But when you're actually trained, you're trained that it is your duty to refuse an illegal order. Now the question is whether or not you would consider that order illegal.

But let's say that a president ordered a strikeout of the blue. What would happen if that guy refused to turn the key in the silo is that he could be relieved of duty. But you could imagine that it would then, quite quickly, if a bunch of people refuse, to become public, and then that might change the conversation.

And I thought about this in the last days of the Trump administration, basically between the election and the insurrection. What if he ordered a nuclear strike on North Korea? And if there are a sequence of people who would refuse, it would become public. But those guys would have to refuse, and the question is whether or not they would.

DAN RICHARDS: So as the example with the US presidents makes clear, there are systems that we could implement to lessen the risk of an impulsive nuclear attack. But I wonder, as we start to wrap up, given all the work, your paper does looking at human psychology, and just the messiness of modeling things like a nuclear crisis with actual real humans. I wanted to end with in this rarefied world of theorists on the topic, and also world leaders who would actually make these decisions, what lessons do you hope they would maybe take in terms of nuclear security?

ROSE MCDERMOTT: Well, I think the most important thing, and it goes back to what you said, Dan, about how you see this in your daily life, because I think that these are universal phenomenon that happens in everybody's daily life. It's just scaled up to bigger larger units and more dire consequences. But it's perspective taking. And by that, I mean, you don't just think about what you see from your perspective, but you try to see what it looks like from the other guy's perspective.

So how does the other person see you and your actions? And you might not be accurate, but just trying to flip the perspective to realize that your perspective isn't the only perspective possible. It's basic marriage counseling.

It's not just you in the room, your perspective isn't the only one, and there may be something about the other person's perspective that you're unaware of. And once you see, oh they're dealing with their domestic audience, oh there's really some internecine politics going on, and their internal structure is more fractured than it appears. That perspective taking like gee, what does it look like from the other side, can really give you insight that might calm things down a little.

REID PAULY: Reid, that's a big, big question you asked. But the way I encourage people and my students to think about it is just that these risks are not going anywhere. Let me put it this way one of the things you see when you read, especially early on in the conflict after the war in Ukraine began.

As you started to see people write about this conflict, as though we hadn't thought about nuclear weapons in a long time. If you have a generation that thinks that war is counterinsurgency, Iraq and Afghanistan style, nation building type war, what it requires is a fundamental shift. And really it's going backwards, unfortunately, and thinking about, OK that's not war really. War is hell.

And war in the nuclear age is civilization destroying. So we are unfortunately rowing in the same boats as our adversaries in the nuclear age. In Nineteen Forty-Five, we invented the ability to destroy ourselves, and we have so far managed, through actual management or luck, managed to avoid nuclear Armageddon. We are here again managing the risks of nuclear weapons.

DAN RICHARDS: As Reid puts it, we will always have to be managing this risk. There is no way out. Even in a world in which you manage to get rid of nuclear weapons, the knowledge about how to build nuclear weapons remains. And so in perpetuity since Nineteen Forty-Five, and now in perpetuity, humankind has to live with this problem of inventing nuclear weapons.

REID PAULY: It's a political challenge that will exist forever, and that has the basic solution of continuing to focus on the problem, educating people about what the problem is, studying how to manage escalation risks of conflict in a nuclear age with nuclear adversaries, and building institutions that try and govern nuclear technology, and make sure that it's being used for peaceful purposes and not for military purposes. That work will continue forever.

It should always be well funded and people should be educated to go into it. And I encourage my students to participate and become involved and learn and focus on it as a challenge. We have more work to do. Every new generation needs to step up and confront these challenges and come up with better ideas than the ones that came before.

DAN RICHARDS: Reid, Rose, thank you so much for talking with us on Trending Globally.


REID PAULY: It was a pleasure. Thank you.

DAN RICHARDS: This episode was produced by me, Dan Richards, and Sam McKeever Holtzman. Our theme music is by Henry Bloomfield. Additional music by the Blue Dot Sessions. If you like this show, please subscribe to it wherever you listen to podcasts. And leave a rating and review on Apple or Spotify, it really helps others to find us.

If you have any feedback for us or questions or ideas for topics or guests for an upcoming episode of Trending Globally, send us an email at trendingglobally@brown.edu. Again, that's all one word, trendingglobally@brown.edu. We'll be back in two weeks with an all new episode of Trending Globally. Thanks.

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