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Evan Sankey: All right, everybody, we’re gonna get started shortly here. If you could take your seats, please. Thank you. We’re about to get started with the second panel here. Thank you. So this morning, we heard from an excellent panel about challenges associated with proliferation to US adversaries going forward. Now we’re gonna talk about friends. A core purpose of US alliances and partnerships is to disincentivize friendly nations from developing their own nuclear arsenals. Beyond that, US policymakers employ a range of carrots-and-sticks, multilateral treaties, extended deterrence promises and consultations, troop deployments, nuclear sharing, first-use nuclear strategies, threats of abandonment, and restrictions on transfers of nuclear technologies. But these policies are costly, and US guarantees have inherent credibility problems. Why should an ally believe the US would threaten nuclear use except in the case of an attack on a US homeland?

Recent developments exacerbate this confidence gap. The continued erosion of global norms against the use of force, the decline of US conventional military advantages, especially in Asia, and the volatility of US domestic politics. The nuclear option is now a matter of internal political debate in several close US allies, including South Korea, Japan, Germany, and Poland. And serious debate about whether nuclear proliferation might sometimes serve US interests has gathered steam in Washington, hopefully including on this very panel.

Joining us to discuss the friendly proliferation debate are three distinguished scholars of nuclear policy issues. Astrid—Astrid Chevreuil is a visiting fellow in the Europe, Russia, and Eurasia program at the Center for Strategic and International Studies. She’s a career diplomat with the French Foreign Service, having most recently served in the Nuclear Nonproliferation and Disarmament Department at the French Ministry for Europe and Foreign Affairs. Her research focuses on European security, transatlantic relations, French defense policy, and nuclear issues, and she is the author of the excellent new CSIS report, Friendly Proliferation: Assessing US Perceptions on Proliferation Among Allies and Partners.

Jennifer Lind is an associate professor of government at Dartmouth College. Her research focuses on the US alliance system in Asia, Japanese security policy, nuclear dynamics on the Korean Peninsula, metrics of geopolitical power, and Chinese political economy. Her latest book is Autocracy 2.0: How China’s Rise Reinvented Tyranny. She’s also the author of Sorry States: Apologies in International Politics, as well as co-author of the excellent international relations blog Blue Blaze, which I strongly recommend. And she’s the co-author with Daryl Press of a piece published just yesterday in Foreign Affairs titled The Broken Nuclear Umbrella: What Comes After Extended Deterrence?

And joining us in the room is Eric Brewer. He is deputy vice president at the Nuclear Threat Initiative’s Nuclear Material Security Program, where he leads work on nuclear nonproliferation, deterrence, and strategic stability. Before joining the Nuclear Threat Initiative, he served as director for counterproliferation on the National Security Council and as deputy national intelligence officer for weapons of mass destruction and proliferation at the National Intelligence Council. His research focuses on preventing the spread of nuclear weapons, managing proliferation risks, and evaluating how nonproliferation goals fit within broader US strategic objectives. His work has been published in The Washington Quarterly, Foreign Affairs, the Bulletin of the Atomic Scientists, and many others.

So to frame our discussion here, Eric, I’d like to start by asking you—what is the rationale for our current policy? You were a member of a recent Carnegie NTI Belfer Task Force, which concluded, in part, that preventing the further spread of nuclear weapons is central to US national security and should remain a top priority. The United States should consistently and vigorously oppose proliferation to any state. Tell us why that is, what US interests are at stake, and what are the costs that the United States is trying to avoid?

Eric Brewer: Yeah. Thanks for having me, Evan, and one quick correction. I was not a member of the task force. I don’t wanna associate myself with that. I was on the staff—

Evan Sankey: Oh, I see. My mistake.

Eric Brewer: —of the task force. But, no, it’s okay. So, you know, I think in answering this question, I think it’s important to kind of go back a bit, right, and recognize that since, you know, roughly the mid-1960s, the United States has had kind of a blanket nonproliferation policy, right? We’ve aimed to prevent proliferation to allies and adversaries alike, and that has largely been true across Democratic and Republican administrations, although I think it’s fair to say certain presidents leaned more into that than others. But I think a big reason that we’ve done that is not for normative reasons per se but because we judged it was in our national security interest not to allow proliferation to either adversaries or allies.

And I think there’s a number of rationales that underpin that, right? And I think those were true in the mid-1960s, and I think for the most part, they’re still true today. So those are things like, you know, allies may not be allies in perpetuity; that allied proliferation could potentially induce arms races wherever it occurs, right? You can imagine if South Korea acquires nuclear weapons, what that might do to North Korea’s calculus or China’s calculus. Because, you know, more nuclear weapons in the hands of more states inherently increases the risk of nuclear war, either accidentally, through miscalculation, or on purpose.

I think, if we’re being honest too, there’s also a belief that allies with nuclear weapons would force the United States to yield a degree of control over that ally and make it harder to manage crises, right? You know, it’s kind of obvious to say, but we can certainly control our own nuclear weapons. It’s much harder to control the nuclear weapons of an allied state. And so there’s a risk that we could get sucked into a crisis or a conflict that we would otherwise prefer to remain outside of or to manage differently.

And I think another big reason is that the process of proliferation itself is dangerous, right? We often focus on kind of once we get on the backside of proliferation, if an ally has nuclear weapons, what are the risks or what are the consequences? But the process of proliferation, which is not a switch, right—it’s not one decision, it’s a thousand different decisions—that very process could easily implicate US security interests, including our security commitments to allies and partners. You can imagine an ally pursuing nuclear weapons and that causing an adversary to try to take action to stop it, either kinetically or through other coercive measures such as sanctions and diplomatic pressure.

And so I think, you know, there’s a number of concerns that we’ve had historically, and I think if you look at the world today, those concerns still bear out, right? The world is a more complex security environment. We have more nuclear weapon states today than we had in the 1960s. And so I think, if you look at this list of reasons, one could say they were overblown, right? Like, a lot of these things never came to pass, but I think the reason is because the United States spent significant effort and time building the international tools, building our own unilateral toolkit, building sort of the nonproliferation regime and the international system to manage them. And so I think if you look at, again, where we are today, the rationale for pursuing and maintaining that same system stands.

Evan Sankey: Thank you. I think it is fair to say that the perspective laid out in the NTI Carnegie Belfer report is still the consensus, but as our co-panelist Astrid Chevreuil found in a recent study, things are changing. Astrid, I was hoping you could walk us through some of your conclusions. You write, “The taboo surrounding friendly proliferation is eroding, giving way to a more open discourse and even public advocacy in some academic circles.” Please tell us a bit about your findings.

Astrid Chevreuil: Thank you very much, and thank you for having me. I’m very glad to be able to present these findings. So one thing that was really striking, when I interviewed 42 experts on nuclear issues, grand strategy, and regional issues, was that all of them told me that it was overwhelmingly discussed in their circles. Even the term is not something that I heard before, and I was really surprised as a European in a think tank in DC to hear this term in the first place when I started. That’s why I decided to do this study, to objectify also this perception. And so all of them told me that it was a discussed contingency to talk about friendly proliferation.

Nonetheless, the main finding really concurs with what Eric said and the findings also of this other report: the consensus still holds, and it’s a minority who advocates for it. Half of the cohort, so 20 people out of the 40 who I interviewed, remain strictly opposed to friendly proliferation, and even the vast majority, 30 people out of 40, emphasize that they don’t believe in a formal shift in official policy of the US for a ton of reasons that I think Eric explained very well. You know, for military reasons, diplomatic, legal reasons, economic reasons as well, that would be very difficult to really measure.

And I also found that there was a divide inside the US expert community on how they perceived friendly proliferation. Basically, what I found is that the more people know about the political, legal, even technical issues related to nuclear issues, the less likely they are to find that friendly proliferation is appealing, because probably they see a lot of constraints to it. But grand strategists and regionalists sometimes were more open to the idea. For the grand strategists, it’s because they see the world in terms of balance of power, and it can seem appealing. It can be an appealing solution to solve some of the complex balances of power between the US, Russia, and China these days. And for regionalists, it’s more a question of strategic empathy, if I may say. They understand the rationale of the allies who might contemplate having nuclear weapons for regional security reasons or doubts about the strength of the alliances they belong to.

Nonetheless, I think that also one of the findings that was interesting is that these different circles don’t interact a lot between them. They work in silos, so they talk past each other. People who are pro-friendly proliferation talk among themselves, within a minority, and people from the mainstream consensus also don’t interact a lot with people who think that friendly proliferation is a good idea. And it causes some problems, in particular in the perception of allied countries, where the discussion is sometimes not very well framed. And so it gives an idea or a perception of confusion inside the US strategy community, an idea of more permissiveness maybe for some of these countries. And so that’s what’s dangerous at the moment, is that there is not really a consensus or at least an image of consensus in the US strategy community for these allies.

Evan Sankey: Astrid, one of your most interesting findings, I think, had to do with the distinction between active and passive types of friendly proliferation. And I think you found that even among the minority of US scholars who are friendly proliferation curious, the way in which they were curious was in terms of the US perhaps stepping back in some cases, rather than actively assisting a friendly country in getting nuclear weapons. Is that right?

Astrid Chevreuil: Yes, that’s right. And it’s also because most of the people who advocate for friendly proliferation or show more openness are from groups of restrainers or conservatives who call themselves realists, whatever that means exactly. But for the restrainers, they prioritize usually recentering the US interest on core, you know, Western Hemisphere or a few theaters, and usually for them, it means placing that priority at the top of the list, and nonproliferation then becomes a second or a lesser important priority for US security. But the idea was really for these people to reduce, in the first place, US engagement abroad without really taking into account the negative impact of friendly proliferation. They didn’t really want to see it. They preferred to actually have this sort of silent acquiescence of the US if some allies were willing to proliferate because it could lead the US to walk away from these theaters. But that was not an optimum solution.

Evan Sankey: Jennifer, in the past few years, I think starting in 2021 or ‘2, you have argued that the US should accept that some of its allies will go nuclear. Yesterday, in Foreign Affairs, you wrote, “US allies are vulnerable, and they are right to take concrete steps to reduce the real dangers they face, whether that means developing their own nuclear deterrent or making other moves that violate outdated US prohibitions. Washington should support them, along whichever path they choose for protection.” And you go on to argue the US should offer nuclear sharing arrangements or in extremis consent to them developing independent nuclear deterrence. Walk us through your case, because you are, I think, the most articulate analyst making these sorts of arguments.

Jennifer Lind: Well, I think my co-author would dispute that, but I appreciate it. Thank you. First of all, thank you so much for having me. This conference is just terrific and this topic that we’re talking about right now, we’re increasingly seeing in the news, and so it just underscores how important it is. So, yeah, I had a very timely release of our article yesterday. The essential argument that I make with Daryl Press, my colleague at Dartmouth and husband, co-author, is that the US nuclear umbrella that we’re talking about was really created for a very different era, whose conditions have changed significantly. So for example, during the Cold War, when this was created, this promise that the United States would put its cities on the line for its allies’ security was just barely credible. We know there was a lot of controversy about it, but it was just barely credible because of the truly global stakes during the Cold War. So Washington knew that if the Soviets gained control of Germany, of Western Europe and so on, this would mean Soviet control of Eurasia, which was unacceptable in the eyes of US leaders in terms of a core security threat.

So today things are different. Conflicts are much more regional in nature. There’s not this threat of global Soviet domination or global anyone domination. And so, for example, a war in Eastern Europe is essentially about the borders of Russia, borders of Russian influence, not about the global balance of power. So that’s a key thing, which is the change in stakes that we’ve looked at.

And then secondarily, it’s the Trump administration’s national security approach, which is one of course of America First. And America First directly contradicts a pledge to wage nuclear war on behalf of your allies, to put your cities at the risk of the adversary’s missiles. So those are the two key things that have changed and we argue have weakened deterrence toward our adversaries and have led a lot of allies to be very concerned as well.

So, in this situation, we don’t argue that here’s the right path. You know, we’re not advocating that the allies get nuclear weapons and so on, but we’re saying, “We get it.” Things have changed so much, the US has changed so much. Their core security is on the line, and they may indeed make this decision, and so the United States needs to think about how to support them.

Eric Brewer: Can I jump in on that?

Evan Sankey: Absolutely.

Eric Brewer: So just to add to what’s been said already, I think all of us can certainly put ourselves in the shoes of our allies and can imagine why they might be contemplating going down the nuclear weapons pathway. But I think as we talk about these conversations that are happening in allied capitals, oftentimes we refer to allied debates about whether or not to pursue nuclear weapons. At least in my view when I look at this, I think it’s important that we draw some distinctions, right? There’s some places where these debates are genuinely taking place, and they’re very serious—I think South Korea is certainly one of them. But there’s other places where I think it would be kind of a stretch to call them debates, right? I think in some cases, you know, you might have a couple of politicians kind of ruminating publicly about, you know, “Gee, wouldn’t it be nice to have nuclear weapons?” And so I think it’s important to kind of draw those distinctions because I’m not sure—and look, I’ll be the first to say, I’m worried about ally proliferation. I agree with the last panel that I think this is kind of where the primary proliferation threats are emerging. But I’m not sure we have a ton of allies kind of pounding on our door, demanding to develop nuclear weapons.

And I think related to that, I think we also wanna keep in mind the barriers that exist to nuclear weapons development, right? I think a lot of the allies that we’re talking about, I think all of them are members of the NPT, right? So they would have to withdraw from that treaty or potentially violate it. And there’s, you know, domestic constituencies within a lot of these countries that are anti-nuclear weapons that are gonna bear on these decisions. I think aside from Japan and maybe Germany through its involvement in Euratom, I don’t think any of them have enrichment reprocessing capabilities, which are obviously kind of the two main pathways to producing material for a bomb. And so, even if they were to desire nuclear weapons, we’re looking at, I think, years or decades of a process underway.

Evan Sankey: But nonetheless, there are some allies, like Japan, like Germany, that could probably go pretty fast. And you know, you brought up in your initial remarks, Eric, that there’s a whole set of things—there’s a gray area between not having nuclear weapons and having nuclear weapons. It’s often talked about in the academic community as like a switch being flipped, but there’s like an interregnum period that could be very destabilizing. Given the rising appeal of friendly proliferation to would-be proliferators and shifts in US interests, possible shifts in US grand strategy, should the US start to prepare itself for a decision by one of its friends to develop nuclear weapons? I mean, should we make preparations other than just blanket opposition to it?

Eric Brewer: Well, I would say we should certainly start to think through what the implications of that would be for US interests. But I think related to that, we should also think through how to best prevent it, right? I think it’s a little bit of an oversimplification just to say it’s a blanket no, no, no, right? As the last panel talked about, I think the United States has developed kind of one way of dealing with proliferation over the past several decades because the primary proliferation threat has been rogue states, right? Like, that’s kind of how we all think about proliferation when we think about it. And I think as they kind of argued, and I would agree with it, we’ve kind of approached this, and I would argue somewhat in a bipartisan way, where the basic strategy is to heap on piles of pressure combined with diplomacy until they decide to sort of choose a different pathway, right?

I’m not sure that’s really the solution set that’s gonna work with allies and partners, right? ‘Cause you can’t—I mean, I guess you could maximum pressure an ally, but I don’t think that’s really the pathway that we would wanna go down, nor do I think it’s a particularly credible one. So I think there’s, and maybe we’ll get into this later, a number of different steps the United States can take to dissuade allies from going down that pathway.

Evan Sankey: One of the features of this debate is the distinction between particularism and universalism. It strikes me that Jennifer’s argument here is that there are particular cases, that there’s a particular backdrop to certain regional problems, like in, say, the Baltics or the Korean Peninsula, where the United States might want to make an exception. And you know, given the broader strains on US grand strategy, we have growing resource constraints, we have rising debate in both of our political parties about first-order issues of what our interests are in the first place. It strikes me that there might be certain cases, and that we have had friendly proliferation in the past. We have three close US partners that possess nuclear weapons; this did not lead to a cascade. You might say it didn’t lead to a cascade because of all the other policies we put in place to prevent the cascade. But nonetheless, there’s a certain aspect to the character of the nine nuclear-weapons-possessing countries that kind of favors US interests, I think. Like, it is better for US interests than not that there are independent nuclear deterrents in Europe. And I wonder whether that same kind of logic might apply to other places. Jennifer seems to think it does in the case of the Korean Peninsula.

Jennifer, you and Daryl Press came up with a very interesting formula for the Baltics or Poland, which I hope you’ll talk about a bit later. But just the idea that thinking in terms of this as a case-by-case problem—which if you look at the history is sort of what we’ve done in the past, we’ve made exceptions before—might also make sense in the future. I mean, you write in your article that there were times in the Cold War, in your 2021 Washington Quarterly article, where we put other interests above friendly nonproliferation and even adversary nonproliferation. Might we do that again? This question over here? Yes.

Eric Brewer: Yeah. Yeah, so, you know, again, drawing on that article, like I think it’s certainly true that in some cases in the Cold War we did put other interests ahead of nonproliferation, right? And in this environment, we have a ton of different national security goals, multiple objectives, and nonproliferation is one of those, and we’re gonna have to kind of figure out how all these weave together. But I wouldn’t quite say that the Cold War was broadly characterized by nonproliferation being put on the back burner compared to other interests. Because, again, I think Pakistan is a pretty clear case of where that happened, but if you zoom out, you could argue in many ways the Cold War demonstrated the willingness of the United States and the Soviet Union to actually subjugate competition to cooperation on nonproliferation, right? I think you look at the fact that both were willing to work together to establish the IAEA, the International Atomic Energy Agency, work together to form the NPT, basically kind of like collude in the shadows to prevent their own allies from developing nuclear weapons.

So I think there’s a track record of cooperation there. That’s not the world we live in today, right? We’re in a very different place today. I think there’s been some pretty significant backsliding on the part of Russia, and certainly China, when it comes to nonproliferation practices, although we of course all agree in theory that proliferation is bad. I think we really sort of lack an agreement on what that means in practice. But I don’t think that means that we sort of chase them down that pathway of making exceptions to existing rules and policies and standards.

And I think this notion of controlling for proliferation or sort of selective proliferation, I fear, is flawed, right? Because I think we can certainly all understand why if South Korea develops nuclear weapons why it would be hard for us to tell Japan no in that case, but I think really the bigger issue is that if the United States makes the decision to selectively allow proliferation, even in one case, I think that fundamentally undercuts our role as the kind of the architect and the guarantor of the nonproliferation system that we’ve developed over time. I think it’s gonna make it much, much harder to rally the international community to cooperate on preventing any cases of proliferation, even adversary proliferation. I think you’ve basically in that case given Russia and China a green light to do the same with their friends and allies. And I worry, quite honestly, that could be the unraveling of the NPT, given the role that the United States has played in creating a lot of the norms and standards and institutions that I think have worked quite well to our advantage.

Evan Sankey: Jennifer, in your early career, your work focused on Japanese security policy. You wrote an excellent paper on buck-passing in Japanese security policy. And as I understand it, you have argued that the common argument you hear that Japan would immediately follow a South Korean nuclear breakout isn’t—that basically we shouldn’t take that at face value. Could you talk us through your thoughts about how Japan would react to South Korea getting nuclear weapons?

Jennifer Lind: Yeah. I think it’s far from an automatic reaction. You’ve brought up the idea of nuclear cascades, and that is, of course, something that we should be worried about and thinking about, and if there are potential proliferators, we should be thinking about what would be the possible cascades that could follow. In Asia, if we are talking about South Korea perhaps moving to acquire nuclear weapons, then many people do talk about Japan as the domino to fall. I think that there’s some reasons for thinking that. Partly that Japan is, of course, observing the same changes in U.S. policy and in the geopolitical environment that South Korea is, and so perhaps it’s feeling some of those same pressures. Although I would argue Japan is, because of the kind of counter-China orientation of the United States these days, I think Japan is actually in very close stead with the United States, probably more so than any country. So I think actually the alliance relations between the U.S. and Tokyo are quite good.

Japan, of course, has the legacy of absorbing two nuclear attacks by the United States, which created a very strong anti-nuclear movement within the country. There were also subsequent events such as the Lucky Dragon incident when U.S. nuclear testing in the South Pacific irradiated Japanese fishermen. There’s of course the 311 disaster in Fukushima. So there’s a very strong anti-nuclear sentiment there. On the other end of the spectrum, Japan does have basically many tons of plutonium. It has the engineering capability, the scientific capability, and can be seen in many ways as pretty far down the continuum, at least technically.

But again, the Japanese public are so very not interested in this at this moment, which is a very, very striking contrast with South Korea. And also, I think that the nuclear threat that they face is quite different. North Korea is fundamentally targeting South Korea, and the Japanese do feel a North Korean threat, but definitely not as intently. And so, I really do think that this would be a momentous decision for Tokyo. It’s not an automatic one, and I think Eric’s laid out lots of the reasons why. This is not just like, “We’ll flip a switch and go nuclear.” This involves international treaties, domestic politics, complicated industrial and, you know, fissile material kit, right? I mean, there’s so many considerations here. It’s expensive at a time where Japan is already kind of straining to meet the burdens of conventional rearmament. So I think, again, for all of the talk of cascades, we really need to not just identify where the potential cascades might be, but to think through, is it really— do we think that would be in that country’s interest? Do we really think that that’s a route they would go?

Evan Sankey: One of the most interesting developments in US foreign policy in the past few years has been our willingness to relax restrictions on transferring nuclear-powered technology to some of our allies. So for example, the AUKUS pillar one program to transfer nuclear-powered submarines to Australia in the future. And just this past year, the decision by the White House to—unclear exactly what we’re gonna transfer to South Korea, but give them the technology or the permission for them to build nuclear-powered submarines of their own. This has been noticed in Japan. You know, the Japanese defense minister has said that they’re also interested in nuclear-powered submarines. Astrid, this was a section of your recent paper asking about what the US policy community thinks are the motivations for these kind of changes. What have you heard? Do—does the US policy community think that this is a step back from US nonproliferation commitments, or that there might be some sort of slippery slope? Tell us about your conclusions regarding that.

Astrid Chevreuil: Thank you. Well, one of the questions I asked during the study to understand the perceptions of US experts was, how did they interpret the US-ROK submarine deal? And I found that there were very different interpretations ranging from people who believed it was a very high risk of proliferation because they believed that the deal had a very important nuclear component, to people who believed that it was completely impossible because it was actually a deal that would be very hard to put into practice and that they didn’t believe it was a threat to the nuclear norm. And my goal was not to find a decisive answer to this question, but more to understand the perceptions. And so the perception was that the US stance on civil transfer was shallower for these experts, and so it was for allies.

But I think it also relates to this grand bargain that we’re talking about from the start, this idea that US extended deterrence and in particular just security guarantees from nuclear weapon states—and that goes also for the US but also the UK and France in Europe, for instance—the security guarantees that they provide to their allies and partners are one commitment that is supposed to have a mirroring commitment from the non-nuclear weapon states, which is, “I will not proliferate, and I will also have access, in restrictive ways, but access to peaceful uses of nuclear energy.” And I think we see the pieces of the puzzle moving.

But maybe one thing I wanted to mention following what has been said, especially regarding the acuteness and the fact that discussions in allied countries are dynamic on these issues but are not revealing an actual intent to go for an indigenous nuclear program in most cases. In Europe, for instance, the threat of going nuclear is used mostly by Poland and Germany, also in Nordic countries sometimes you have some experts, also a minority, advocating for it. But usually they use it as a bargaining chip to gain more security guarantees from the US, and not actually show that they’re willing to go down that perilous route of proliferation, which would be very costly for them. And we’ve mentioned the cost for the US, but also for allies it would be very costly to proliferate and to become a friendly proliferator.

At the military level, for the US we see this risk of control of escalation in a lot of contingencies, but for allies who don’t really have the nuclear literacy, if I may call it like this, it’s very dangerous to imagine that they would have to choose how to do, what to do in case of, for instance, a hybrid scenario or how they would just frame their doctrine. So there’s this military unknown that is very dangerous. It would also likely cause entanglement for the US, or deterrence failure in worst-case scenarios. In terms of diplomatic and legal issues, it has been mentioned by Eric that it would probably be the end of the NPT if you have this sort of double standard between selective allies and another stance towards adversaries. But also, for allies who would be willing to go nuclear, that would probably mean, at least at the beginning, being banned from the international community, and so the reputational costs would be huge.

And eventually in economic terms—you’ve mentioned it as well before, Jennifer—a lot of allied countries struggle to invest in conventional capabilities that are the ones that they need the most at the moment, in particular, I think in Europe. And so extended deterrence provides known gains for them in terms of stability, while friendly proliferation would likely have very negative impacts, especially in the window of vulnerability of building up even this movement of hedging that you talked about too, when they would try to get to this capability. Even those who are advanced, you don’t do this overnight. We sometimes hear, “Oh, now with ChatGPT you can build a nuclear bomb,” but it’s not true. Like, getting to an act—and that’s one of the reasons why Iran didn’t get one overnight too. So I think that’s also something to put back in the debate because the questions that it raises for the US are also questions that it raises for allies alike.

Eric Brewer: Can I jump in?

Evan Sankey: Go ahead.

Eric Brewer: So I just wanted to—I think, Astrid, you made some really good points there on sort of the conventional forces piece of this, and Jennifer, you as well. And I just think, personally, I am all for enabling allied conventional capabilities, right? I think if we’re gonna say no to nuclear weapons, we have to say yes to conventional capabilities. And so I think I just wanna sort of put a marker there.

But I think on this notion of civil nuclear energy, I wanted to come back to that for a second, right? I think this is one of those issues where I think there is a significant risk that if we open the door to enrichment and reprocessing in some of these countries who are considering this capability—Saudi Arabia being one of them, South Korea being another—I worry that that’s gonna be a very difficult door to close. And again, the concern is that those are kind of the key capabilities that countries can use to develop nuclear weapons. And so I think, you know, I do worry about some of the directions that US policy is trending in this moment. And I also fear, sort of getting back to this, how do we look at the debate taking place within the United States on these issues? I’m not sure everybody quite recognizes the connection of those capabilities to nuclear weapons. I think for some they sort of say, “Well, they’re our allies. Like, why can’t they have them?” Right? Like, or, “Why can’t we give them all the civil nuclear energy technology?” And so I worry about the details of what makes nonproliferation work getting lost in some of these broader debates about our relationship with allies.

Evan Sankey: Are—are you also worried, in addition to civil nuclear, are you also worried about the military applications of nuclear reactors to nuclear-powered submarines, for example, the AUKUS or the South Korea deal? Are you worried?

Eric Brewer: So, I mean, my concern about the submarine deal in the case of South Korea is that, again, based on, I think, some of the reports we’ve seen, it’s an open question whether or not the fuel for that submarine is gonna be produced and enriched in South Korea. I think that is the concern there. I’m a little less concerned about AUKUS because it doesn’t deal with it in that same way.

I will say, on the positive side of civil nuclear energy, I actually do see a significant opportunity for the United States in civil nuclear energy because I think we’re seeing a pretty significant increase in that technology across the world. And I think historically, looking back, the United States used its position in the civil nuclear energy market as a leader in that space to be able to insist on pretty strong nonproliferation conditions in the transfer of those technologies to its partners. And I think there’s a strong case to be made that it would be wise to invest in trying to recoup some of that leadership capability in this new interest in nuclear energy, and be able to sort of write the new rules of the road, so to speak, when it comes to the nonproliferation and security conditions around the export of these technologies.

And I would add, doing that has benefits not just for nonproliferation, right? That cuts across a variety of different interests. We’re talking about how these interests intersect when it comes to ally proliferation. That has benefits for strategic competition; that has benefits for energy security. And so I think there’s a lot of value to be had in pursuing that type of an approach.

Evan Sankey: Jennifer, one of the strengths of your Foreign Affairs piece yesterday is that you drew out the extent to which at least some of our current extended deterrence commitments are very dangerous bluffs, and that at the end of the day, these are promises to put American cities at risk on behalf of a country which is not the United States. For any of you—this is to the whole panel, I guess whoever wants to jump in first—how do you assess the risks of extended deterrence going forward? Like, are they—you know, obviously we have not had a nuclear war so far, but is Jennifer right that the risks are rising in such a way that not just our allies, but also us should think more urgently about whether an alternative policy framework is needed in order to secure the United States itself? Does anybody wanna jump in?

Jennifer Lind: Can I jump in? Yeah, sure.

Evan Sankey: Go ahead.

Jennifer Lind: Yeah, I just wanna clarify, building on what you said, that that is really the core assumption here, which is that the nuclear umbrella, as the title says, is broken, is really strained. So it brings us back to why are we having this conversation today, a conversation that none of us wanna have. We don’t want our allies to get nuclear weapons. We don’t want nuclear weapons to spread. But why is this conversation being kind of put before us? And it’s because of the conditions that I mentioned and how they’ve changed over time. This has led to deterrence being weaker, and so our allies are feeling it and our adversaries are watching these same trends, too. And so if extended deterrence is weakening, deterrence is weakening in these key places at a time when the North Korean threat to South Korea is growing because of strides that they’re making in North Korea and their nuclear program, and at a time in Europe when the Russians have grown more aggressive.

And so our allies are feeling that they have an increased security threat, a core security threat that is not being met. And so I just wanted to remind us that that’s what’s in their minds. And so while we’d prefer that they just said everything’s fine, ultimately it’s not gonna be up to us. We can influence things; we have influenced things. But if a country, a sovereign country, decides its core existential security interests are at risk, it’s its own decision whether or not it’s going to acquire nuclear weapons. So this whole conversation and US foreign policy conversations about this in general tend to say, “What do we think about this? Oh, I don’t like this. We shouldn’t encourage this.” But remember, it might not be up to us.

Eric Brewer: Happy to jump in. Yeah, I agree with a lot of what Jennifer said, right? I mean, I think fundamentally, of course, the decision is gonna rest in the hands of our allies. I mean, I don’t think that means we don’t have an interest in trying to shape those decisions and to shape their calculation. And I would completely agree, right? I mean, I share the concerns that allies have about US extended deterrence and about US reliability broadly; I think is where a lot of that concern lies. But I’m not sure ending extended deterrence is the solution to that problem, right?

I think, looking back at some recent examples, the Washington Declaration that the United States did—I think it was in 2023, somebody correct me if that’s wrong, under the Biden administration with South Korea, right? I think that potentially shows an example of a useful approach of how to handle these allied concerns which again, I think are very real, right? In that it set up specific types of mechanisms, specific consultative bodies where the United States and South Korea could come together, share information, do more joint planning, continue to revisit how all of this is working and how all of this is functioning, and to do that in a way that was very strongly rooted in South Korea’s commitment to not pursuing nuclear weapons. Is that gonna solve South Korea’s concerns? Well, has it solved South Korea’s concerns totally? Probably not. Is it gonna solve them forever and ever and ever? Of course not. But I’m not sure we can sort of put the task on ourselves to solve those problems forever and ever and ever. They are recurring to various degrees, and so I do think that that’s one example of a type of approach that could potentially help down the road. Of course, those have to be tailored for various situations for various reasons.

I also would say that I don’t think we should assume that if allies get nuclear weapons, our extended deterrence mission would end, right? I don’t think that’s an assumption we should make. It certainly could—there could be an administration that says, “Fine, you’re on your own.” I’m not sure that’s gonna be the case. And so I’d say, if you don’t like the cost of extended deterrence or if you’re skeptical of those costs, I’m not sure allied proliferation is a good solution for those. Yeah.

Evan Sankey: Go ahead, Astrid.

Astrid Chevreuil: If I may add—just two sentences because I agree with what has been said before. But I think also if you take the perspective of allies, it would mean that you trade a proven collective security guarantee for, you know, an isolated, contested nuclear capacity that you don’t really know how to use. And so that’s something also to take into account for allies; I think that’s something they have on their mind.

But in the recommendation section of my report, one of the things I really tried to do is actually to propose recommendations that are both for the US and the allies to think about this bargain together, this bargain of extended deterrence and nonproliferation. And in my view, in a lot of capitals, allied capitals, this idea of an indigenous program is entertained because they have lost sight of the fact that there is a link between the two still. Even though I agree with what you say, Eric, that that could exist maybe in practice, but I think in theory and to prevent friendly proliferation from happening, I think we should actually have a more formalized linkage between extended deterrence and nonproliferation, and being very clear about the fact that the operational viability of extended deterrence—it’s like the political commitment, all the technicality also that’s around extended deterrence—would probably dissolve for the ally who decides to choose the nuclear path. Which is I think something that is missing in the conversation now because we took it for granted for a long time, because we didn’t need to discuss that. But now that there is a heightened tension on this trade-off—and I think Jennifer’s article shows that—I think now we should make it clearer and maybe have an explicit declaratory policy against friendly proliferation that would show the link between the two actually.

Evan Sankey: All right. Thank you. We’re gonna use our last almost 10 minutes for Q&A. We will be taking questions both from online and in person. The online audience may join the conversation and submit questions directly on the event page, Facebook, YouTube, and on X. We have microphones in the room. Please speak clearly and directly into the microphone, announce your name and affiliation, and please phrase your question in the form of a concise question. Yes, ma’am. Right there. Yep.

Maria Razborova: Thank you for the panel. My name is Maria Razborova. I am a junior at Georgetown University School of Foreign Service, and my question is about the role of Russian nuclear threat credibility. And so given that Putin has been repeatedly using nuclear rhetoric, which has mostly seemed to fail in achieving political objectives of deterrence, how does this impact the credibility of Russian nuclear threatening, and how does this in turn impact whether the European allies are seeing this credibility as a reason to proliferate?

Evan Sankey: All right. Effect of Russian nuclear threats on friendly proliferation. Astrid wants to go. Astrid.

Astrid Chevreuil: Oh, yeah. Thank you. I wasn’t sure if we were taking several questions, that’s why I didn’t say anything.

Evan Sankey: Go ahead.

Astrid Chevreuil: Well, it’s definitely a part of the conversation in Europe, trying to figure out what were the effects of the Russian rhetoric. But I think one main concern for Europeans is actually that this use of the coercive nuclear rhetoric is what has helped Russia also try to dissuade the support of Ukraine during the conflict. It has failed in a lot of instances, but it’s still a very effective mean, in particular for public opinions in Europe. And it has actually put the nuclear topic back on the table for a lot of Europeans, and all the debates that we were mentioning previously about indigenous nuclear programs often stem from this fear of Russian nuclear rhetoric and even sometimes the idea that Russia is acting as an axis with other adversarial powers. It doesn’t mean though that it’s encouraging Europeans to go down that path because they see the Russian arsenal, they see the balance with the US, and they frame their thinking in terms of “we should keep extended deterrence because so far this is what has worked to repel Russian coercive actions and use on the ground.” So I think it actually goes in the direction of supporting extended deterrence instead of friendly proliferation.

Evan Sankey: Yes, sir.

Steven Snyder: Steven Snyder. Assuming for the sake of argument that Israel has a nuclear deterrent, how likely is the US to be able to control their use of it? And if the US cannot, what would be the implications of that?

Evan Sankey: Israeli nuclear deterrent and US foreign policy.

Eric Brewer: I’ll take a stab. Sure. So assuming Israel has a nuclear arsenal, I mean, I think the United States has very low likelihood of influencing their decision to use that on any given incident. Although I would say, I think one thing that the most recent conflict in the Middle East shows is that when the United States government—when the US president and others—weighs in with Israeli leaders, that matters. That does have an influence on their calculation, right? And I would go back to under the Biden administration, I think the US government’s attempts to dissuade Israel from responding more strongly to some of Iran’s attacks on Israel, I think that had a role in influencing Israel’s calculation. Fast-forward to the Trump administration, I also think the perception and ultimately the willingness of Trump to give a green light to Israel to strike Iran also influenced their calculation. So I think there’s obviously some opportunity for that influence to happen.

Evan Sankey: Yes, ma’am.

Sarah Khan: Hi. Thank you. This is a great panel. My question is more about the debate surrounding friendly proliferation.

Evan Sankey: Your name and affiliation.

Sarah Khan: Oh, sorry. I’m Sarah Khan, and I’m with the Institute of Global Affairs. My question has more to do with if friendly proliferation happens, what exactly, what kind of procedures would have to take place? All three of you have mentioned treaties and arrangements, et cetera. Are we talking about control over the nuclear fuel cycle or fissile material? And say we’re in a world where there’s an ally that would like to proliferate, how could the US—

Evan Sankey: Have control over that proliferation.

Sarah Khan: —and I mean sort of taking a step beyond the “please don’t proliferate.” Say that, Jennifer, to your point, a sovereign country, if they wanna do it, they’ll do it. So what kind of actions can the US take over the nuclear fuel cycle to maintain control over that proliferation? Thank you.

Evan Sankey: Sounds like a question for you.

Eric Brewer: Happy to take on that one. Just to clarify, you were saying, like, what steps can the United States take to prevent ally proliferation, or if it happens?

Sarah Khan: Well, so I guess sort of both. My question is more about fissile material production, ’cause that seems to be the key element, right, in becoming a nuclear weapon state, or at least the first step of it. So I guess my question is what kind of steps is the US thinking in terms of its allies in these debates that we’re having about weakened extended deterrence? And to Astrid’s point of perhaps we need more institutionalization of what is extended deterrence and how does it interact with nonproliferation, what kind of—you know, I guess I’m asking you to look into the crystal ball of fissile material production and control.

Eric Brewer: Yeah. Thanks for the question. I’ll tackle the nuclear material production and maybe perhaps expand it a little bit, right? I mean, I think, again, the United States has a set of conditions by law that govern the transfer of civil nuclear technology, right? And those oftentimes contain restrictions on what that country can do with that material, with or without US permission. And so that’s something that’s baked into a lot of agreements, and there’s oftentimes where those agreements go further, and countries accept additional restrictions on what they can do with that material, and that’s obviously been the goal in a lot of cases, right? But we haven’t always reached that goal in all of our civil nuclear cooperation agreements.

I think, looking a little further down the road, sanctions is obviously a tool that the United States could potentially use to either dissuade an ally or punish after the fact that it happens. I think when we think about sanctions, a lot of us think about, like going back to the last panel, Iran sanctions, right? And we see these sort of executive orders coming out of the White House. But there’s also sanctions that are on the books by law when it comes to nuclear proliferation. And some of those—I think it’s the Glenn Amendment and it’s the Arms Export Control Act—that would impose some pretty severe consequences on any country, including allies, if they were, for example, to test a nuclear device. Those consequences, they have no waivers, right? There’s no waivers to those provisions. So, you know, if you didn’t want to enforce those, a new law would presumably have to be passed. So that’s, I think, something that would come into play in the future if an ally were to proliferate.

And I think, you know, when it comes to ally proliferation risks, there’s a tendency, when it’s if it’s not a severe case—right, if the ally isn’t bolting for the bomb—to try to handle this behind the scenes and to try to work things out as best as possible, diplomatically, sort of out of the spotlight. And I think if you look back, that was the approach the United States took to South Korea and Taiwan, at least initially, in the 1970s and the 1980s. So I think there’s a case to be made that that’s sort of a preferable pathway, and you only need to go get sort of some of the more public steps or some of the more severe kind of pressure mechanisms if things go in a direction that we don’t want.

And I would finally add on the civil nuclear energy front, one of the tools that the United States has in the toolkit is that if an ally were to break its commitments to the United States using US nuclear technology, the United States can request the return of that technology, right? And that would really endanger that country’s civil nuclear energy goals.

Evan Sankey: We are at time, so I’d like to thank Astrid, Jennifer, and Eric for joining us today to talk about this challenging topic. We will now take a 45-minute break for lunch. Please join us back here at 1:05 PM for our final panel on US nuclear forces, moderated by Ben Giltner, our policy analyst in our Defense and Foreign Policy Studies program. For those of you in the room, lunch will be served up the spiral staircase, in the second floor George Yeager Conference Center. And again, we look forward to seeing you all back here at 1:05. Thank you.