EXPERT INTERVIEWS — The arsenals of nuclear powers are growing, the number of nations with nuclear weapons may soon rise as well, and Russia has used the threat of nuclear weapons to fend off more robust support for Ukraine. After a long period of global nuclear disarmament, the world is heading in the other direction – and experts fear the trend may be hard to reverse.
The recent headlines are ominous, and they come from many corners of the world: Beyond its Ukraine-related threats, Russia is reportedly considering the use of nuclear weapons in space; China is growing its arsenal faster than any other nation – by far – a pace that appears linked to its regional ambitions; and this week the U.N.’s nuclear watchdog said North Korea had grown its nuclear weapons program “exponentially.” Meanwhile, U.S. allies including Japan, South Korea and Saudi Arabia have all said they may develop nuclear weapons of their own, and last month, Poland’s president suggested publicly that with an increasingly assertive and aggressive Russia to the east, and questions about the Trump administration’s commitments to Europe, nuclear weapons should be positioned on Polish soil, as a deterrent to Moscow. Surprisingly, perhaps, Iran may offer a window for hope in this domain – given the glimmers of hope that ongoing U.S.-Iran talks may lead to a scaling back of that country’s nuclear program
The Cipher Brief spoke about the state of global nuclear proliferation with three experts: Ankit Panda, author of the just-published The New Nuclear Age: At the Precipice of Armageddon; Ambassador Joseph DeTrani, a Cipher Brief expert, and an expert on nuclear proliferation; and John Erath, Senior Policy Director for the Center for Arms Control and Non-Proliferation.
The interviews have been edited for length and clarity. You may watch them at The Cipher Brief YouTube channel.
THE EXPERTS
The global picture
Panda: The start of the Ukraine War really crystallized for me that something was fundamentally shifting in the global nuclear order. In 2021, we got pretty good public evidence that China had embarked on a significant buildup of its nuclear arsenal. Many people will recall the U.S.-North Korea crisis under the first Trump administration; the Iran crisis that continued after the United States left the Iran deal; and then Vladimir Putin initiates a major land war in Europe, backed by nuclear threat-making. Together, this changing geopolitical environment, the arrival of new technologies, the shifting role of the United States in the international system, all collide in a way that really does meaningfully shift the thematic resonance that nuclear weapons have today in international politics.
The roughly 30-year period that followed the end of the Cold War was a period of relative optimism — nuclear weapons receded from the center of international politics to the periphery. Unfortunately, I think beginning in the 2020s and probably for the coming decades, nuclear weapons are going to be back at the center.
Erath: There's some good news and some bad news. The good news is that 80% of the nuclear weapons that ever existed have been eliminated. So that's a significant achievement for arms control and disarmament. And I don't want to lose sight of that. But in the past few years, we've seen the trend reverse. In 2022, for the first time since the end of the Cold War, the world ended the year with more nuclear weapons than it began. And this is largely due to the ongoing buildup in China, as well as some additional construction of nuclear weapons, in North Korea, and possibly in India and Pakistan as well.
One of the key inflection points [was] in 2014. That was the first time Russia invaded Ukraine and seized Crimea and other pieces of Ukrainian territory. At that time, there was a great deal of noise about this, to the tune that we don't want to risk a nuclear war – we have to be very careful with Russia and not overreact. And I think the Chinese in particular paid a lot of attention to this and learned the lesson that with massive nuclear capabilities, you get a greater degree of freedom of action internationally. And as they contemplate military solutions to the issues they have with all of their neighbors, or most of their neighbors anyway, that freedom of action is something that they would want to have as an option.
The world is going toward a place where more nuclear weapons are seen as providing more security. That's something of a fallacy. If, as the doctrine of the United States maintains, nuclear weapons are for defense and deterrence, if what you're doing is deterring an adversary from using nuclear weapons against you, you don't need to match them one for one to do this. Nuclear weapons are so destructive that any prospect that they might be used is enough to create some level of deterrence.
The U.S. nuclear umbrella
Panda: The United States extends its nuclear deterrent to more than 30 countries around the world. And that's not something Washington does out of shared values or interests with these countries, although that certainly was a part of the story over the last 80 years. But it's really been an important nonproliferation tool for the United States. The United States has invested over the decades in assuring these countries, telling them that they don't need their own nuclear weapons because the United States has their back. That's been an extremely difficult thing to do.
Today in the 2020s, particularly in the second Trump administration, there has been quite a bit of malaise setting into the assurance agenda. Allies don't feel particularly good about the relationship with the United States in many cases, about the reliability politically in Washington. And so unsurprisingly, that is leading to these conversations from Warsaw to Seoul to Berlin and elsewhere that nuclear weapons might be necessary.
Erath: With a U.S. leadership that is perceived as being somewhat mercurial, it has exacerbated some of these concerns. The guarantees are still there. But at the same time, you have a leadership in the United States that has increased the pressure on the allies to do more to carry their share of the burden. This has been something that all U.S. administrations, Republican and Democrat, have been united on for decades, but now there's a new twist where there is the implication that the U.S. may do less if the others don't step up. And that is what is introducing this element of unease.
The view from Europe
Amb. DeTrani: Given what Russia is doing in Ukraine with its war of aggression and Putin's threat to use tactical nuclear weapons and beyond even strategic nuclear weapons, Poland has raised its hand and said, Look, we need some capabilities here. And we want to go back to where we were over 30 years ago and have, if you will, tactical nuclear weapons so that if there is a Russian onslaught, we could respond. It's the element of deterrence; if Russia knows Poland has these, then logically, aren't they going to think twice about doing something untoward to them?
Panda: Poland is one of the Allies that's now a lot more interested in nuclear weaponry. Is the right path ahead for Poland to build its own weapons, or can Poland host NATO nuclear members? The United States bases nuclear weapons on the soil of five NATO allies. Poland is not one of them currently. So one of the ideas that's been part of the Polish debate is potentially to bring American weapons to Polish soil.
Erath: The French and UK deterrence are much smaller [than the U.S.], and are designed to deter against particular aggression or coercion to one country and one country only. They have not been, in the past, dedicated to the defense of the NATO alliance as a whole. So they would need to shift their doctrines greatly and they would probably need to add to the nuclear capabilities. In the case of France, this would be very difficult to do because they are in a dire financial condition right now. They don't have billions of euros to spend on increasing nuclear facilities. It's difficult to see how the French could take on additional commitments in this area right now.
The view from East Asia
Amb. DeTrani: The majority of people in South Korea believe South Korea needs a nuclear weapon as a deterrent to North Korea. It's as simple as that.
Why now? One, we’re not talking to North Korea. Two, North Korea now has now memorialized in its constitution that South Korea and the U.S. are its enemies. Three, North Korea now is aligned with the Russian Federation and sending troops there. Four, they're getting ballistic missile assistance, nuclear assistance, satellite assistance from the Russian Federation, areas that Russia has a lot of expertise with. So if you're sitting in South Korea and you’ve got Kim Jong-un saying you're the big enemy and they're building up their nuclear weapons capabilities, with the Hwasong-19 that can reach the whole of the United States, you've got to be concerned.
And there's no question that Japan is very concerned about their security. [The U.S. has] the extended nuclear deterrence commitments. [Japan wants] to hear about those commitments. They want to be reassured.
I think the credibility of the United States is one of the key factors that has over 70% of the population of South Korea believing they should have a nuclear weapon, and Japan wondering about our commitments. They just need reassurances. But I'm not sure those reassurances would do it. I think there's a good likelihood that both South Korea and Japan will pursue their own nuclear weapons.
Panda: Japan and South Korea exist in geographic proximity to each other and to a number of nuclear armed countries that don't have very good relations with either of them.
In Japan, being the only country to have suffered nuclear attacks, there is a level of public neuralgia around the suggestion that Japan should acquire these weapons. Post-Ukraine, public opinion has shifted in Japan about national defense matters — but nuclear weapons are still a bridge too far. That said, there have long been quiet discussions among what I would describe as strategic elites in Japan, the national security experts, national security advisors and defense thinkers, about what the country might need to do in a world where the United States is no longer reliable. And of course, making the jump from those private conversations to a public case for nuclear weapons acquisition is a tall order.
When we turn to South Korea, we have a very different picture. We have public opinion polling for more than a decade now showing support in the realm of anywhere between 60-, 70-plus percent of the public seeing the acquisition of nuclear weapons as beneficial. It's bipartisan. You can be a Korean conservative or a progressive, and you might have your own theory about why the country needs nuclear weapons. The theories are distinct, but there's a lot of public support.
And it's not hard to see why. They have a nuclear armed neighbor to the North that frequently makes threats of nuclear use.
In the case of both Japan and South Korea, unlike perhaps Poland, there is no France or UK. There is no alternative like-minded country in their region that might be willing to substitute for the role that the United States plays.
The Ukraine lesson
Erath: There's been a lot of confusion over this point. Ukraine didn't really have an option [in the early 1990s]. It did not have the means to employ the nuclear weapons that were left on its territory when the Soviet Union ceased to exist. It didn't have a way to maintain them safely. The launch codes were all in the hands of the Russians. So it was not giving up nuclear weapons — they did not also give up the capability to use the nuclear weapons, because they never had that.
But that said, it's possible to make the case that if Ukraine did have nuclear weapons, they would not have been invaded as they were. And it was the choices that were made in 2014, when the first invasion happened, that put us where we are today. The priority was placed on avoiding nuclear war, and that's a reasonable priority to have. But it led to the so-called Minsk process, where the war was basically put on hold and Russia was allowed to continue its occupation pending some sort of settlement to be figured out later. That didn't work. Russia just continued to occupy Ukrainian territory, never got into a settlement process that was in any way legitimate. And as soon as they felt that they had the military upper hand, they invaded again.
So it is possible to argue that nuclear weapons could have prevented that. I think that it's a much more complicated question than that. But the significant thing is that Russia has been using its nuclear weapons very effectively during the current war, not in an explosive way, but as means of diplomatic blackmail. The United States and NATO countries have constrained, from the beginning, the amount of security assistance and the types of equipment they were willing to give to Ukraine out of fear that it could lead to nuclear war.
Panda: It is true that Ukraine physically retained on its territory what would have represented the third largest nuclear arsenal on Earth after the end of the Cold War when the Soviet Union broke up. But of course, the Ukrainians didn't actually have the ability to control those weapons. And so in a way that wouldn't really manifest what many of us would consider to be a nuclear deterrent capability.
Of course, given the evidence and the information the Ukrainians had in the 1990s, it seemed like a prudent move to rejoin the international community and not seek the bomb and gain security assurances. But I think Russia's war has sparked this narrative that Ukraine made a mistake.
Amb. DeTrani: In the Budapest Memorandum of 1994, 1,700 nuclear weapons were given to the Russian Federation in addition to intercontinental ballistic missiles. What did Ukraine get in return? Security assurances from Russia. But Russia invaded Crimea in 2014. I heard this many times from the North Koreans. Security assurances are a piece of paper. You could tear it up or you want us to dismantle our nuclear weapons capabilities.
China’s nuclear arms race
Erath: China is building nuclear weapons as fast as they can. The Chinese arsenal has roughly doubled in the last decade and shows no signs of slowing down their buildup. So the situation is very insecure out there right now.
Panda: China's decision to essentially abandon decades of what had been a level of comfort with a fairly small nuclear arsenal is one of the key drivers of the geopolitical risks that I think are contributing to this new nuclear age. Between 2020 and 2025, China has been without a doubt the world's fastest-growing nuclear arsenal. They have already, by many accounts, roughly quadrupled the size of their nuclear arsenal from 2020. In 2019, for instance, the U.S. Defense Intelligence Agency publicly said that China was assessed to have nuclear warheads numbering in the low 200s, smaller or roughly around the size of the UK's nuclear arsenal, despite being a country of 1.4 billion people with vast national resources and a very quickly growing military in all other regards.
At some point, something shifted in China. We don't fully understand why. There's a big debate among American scholars, among analysts of Asian security, about why China has now decided to make this change. But leaving aside the why for the moment, the what is very clear. We can see with our own eyes and satellite imagery that China is building hundreds of new silos for intercontinental missiles. In the western part of the country, China is building a new set of space-based early warning satellites to support potential shifts in its nuclear posture.
And all of this is, of course, raising anxieties in East Asia and in the United States about what might need to be done. And especially for Washington, the unprecedented situation that I think Americans are now contending with is living in a world with two superpower adversaries that are nuclear states.
For the longest time, America had to worry about Russia. And we did arms control, focused on deterring Russia primarily. China used to be what we called the “lesser included” case. Basically, any nuclear arsenal the U.S. maintained to deter Russia would be sufficient for dealing with China in any contingency. That is no longer true. And that's really opened up the aperture on what the United States should do going forward.
The search for solutions
Amb. DeTrani: I think it has to start with New START, which expires in February of 2026. The United States and Russia were dismantling their nuclear weapons, and now they've stopped doing that. And Putin is saying, we don't want to talk about arms control. That's a thing of the past. We're going to build and we're going to build. And certainly the U.S. is responding to that because we're upgrading our, if you will, nuclear deterrent, because we're just not going to sit here and watch that go on with Russia.
If you're a small country sitting and watching these major countries say that we're not interested in arms control, what would you do then? You have assurances from allies and partners, but you've got to think, I appreciate your nuclear umbrella, but we need our own nuclear weapons.
Panda: My day job is to think about ways to reduce and limit nuclear risks. And fortunately, there's no shortage of ideas. There are really innovative technologies that can be used to enable new types of arms control and verification. There's new non-nuclear capabilities that might reduce the salience of nuclear weapons, potentially giving the countries that see nuclear weapons as an appealing pathway, an alternative that might not demand nuclear proliferation with all of its attendant uncertainties and costs.
The big problem today, of course, is political and geopolitical. One of the predicates for arms control, as we've seen through history, is mutual interest. Arms control is not a set of handcuffs that we apply to our adversaries to constrain them in ways that advance our interests. It's always been a cooperative endeavor between adversaries. During the Cold War, the United States and the Soviet Union had many disagreements, but especially after the Cuban Missile Crisis, which was the most dangerous period of the nuclear age writ large, they determined that relying on deterrence without any guardrails or any supporting systems of negotiated restraint was simply too dangerous. And it took decades to get to the point that we find ourselves in today.
That is the fundamental question. How do you restore those political conditions? Donald Trump's been interesting because he's talked about nuclear weapons as an existential threat. He's talked about an interest in what he calls denuclearization, or negotiations essentially with Russia and China. So he might have something of a Ronald Reagan-esque instinct around these issues that could lead to an interesting breakthrough. That said, I'm not particularly optimistic in the short term.
Erath: [The Iran nuclear talks are] very encouraging. I'm a professional diplomat, so I always think that talking is better than fighting. But it really is the key here that there's an old adage that if the only tool in your toolbox is a hammer, every problem looks like a nail. Well, if the only tool you have is military force and coercion, then that's the tool you're going to use. And that leads to all sorts of unfortunate consequences. We need to be using the other tools that are available — economic incentives, diplomacy, better public information — so that it is understood that using nuclear weapons is never an option, that the destruction that they would cause is too great to risk.
And to be very clear about what we mean by deterrence, we should not be in an arms race where if China builds a nuclear missile, the U.S. has to build one or two. We need to understand that it takes a relatively small number of these weapons to deter any possible nuclear-backed aggression against us. And with that clearly in mind, we should then look at how we create conditions as we did after the Cold War that are favorable to the further reduction of the overall number of nuclear weapons in the world.
Ethan Masucol contributed reporting.
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