May 2025
By Ulrich Kühn

Europe is in turmoil. Polish Prime Minister Donald Tusk is calling for his country to “reach for the most modern capabilities also related to nuclear weapons.”¹ The incoming German chancellor, Friedrich Merz, finds that, “We need to have discussions with both the British and the French … about whether nuclear sharing, or at least nuclear security from the UK and France, could also apply to us.”² In turn, French President Emmanuel Macron is ready to “open this discussion … if it allows to build a European force.”³ At the same time, the European Union Commission is suggesting a $900 billion package to “rearm Europe” with the latest weaponry while Germany has signaled that it could start spending more than $450 billion on defense. Not since the Cold War years have Europeans felt so threatened. Many wonder whether Europe and the United States are still allies.⁴

All this is the result of two men’s ambitions. The one sitting in the Kremlin, Russian President Vladimir Putin, is waging the bloodiest land war on European soil since the guns of World War II fell silent. The other one, U.S. President Donald Trump, re-entered the White House having  pledged to end Russia’s full-scale war in Ukraine “within 24 hours.”⁵ His tactics include cozying up to Moscow, pressuring Kyiv into submission, and sidelining European allies. Putin turned up the heat in 2022 and Trump closed the lid three years later. Europe is a pressure cooker, and the temperature is quickly rising.

Frantic calls for European nuclear deterrence are hardly new. They were a constant background noise to Trump’s first four years as president,⁶ but this time is different. There is now a profound sense among Europeans that “Donald Trump will no longer uphold NATO’s mutual defense commitment unconditionally,” as Merz put it.⁷ Breaking with his predecessors, Merz is openly courting Macron, who for years had offered Europe-wide discussions on the role of French nuclear forces in European security. Another difference: Germany now brings the resources and willingness to invest serious money in defense. Some officials in Berlin have already hinted at German co-sponsorship of the French arsenal.⁸

Underlying all of this is an acute feeling that time is running out—that this is Europe’s last chance to stand on its own feet militarily; that Ukraine’s fate may ultimately hinge on European determination to help prevent a full Russian victory; that soon, the United States might not only turn away, but turn against Europe. Lately, some commentators have started to warn that this summer could be the last that Europeans enjoy peace.⁹ Yet, would a new nuclear weapons arrangement really make Europeans safer?

Deterring What?

What should European nuclear deterrence deter? The two most prominent answers to that question are a Russian land grab in Eastern Europe and Russian nuclear blackmail.¹⁰ The latter is based on an ambiguous reading of recent evidence. On the one hand, Russia has constantly sought to manipulate Ukraine’s military supporters with its hostile nuclear rhetoric.¹¹ The result is mixed.¹² Yes, Moscow has slowed Western military support to Kyiv, sometimes significantly, and prevented more forceful responses, such as a no-fly zone over Ukraine. Yet, the Kremlin has not stopped the steady flow of military hardware, including weapons that could strike deep into Russian territory.

Russian nuclear blackmail against Ukraine has been even less successful. Kyiv has continued its fight for survival no matter what Moscow has threatened, even invading a part of Russia. The war’s empirics corroborate nuclear scholarship, which has found that nuclear blackmail is rarely successful¹³ and that nuclear deterrence against non-nuclear attackers may even have no effect.¹⁴ As such, the nuclear blackmail justification for European nuclear deterrence is rather shaky.

The land-grab argument seems more convincing. Accordingly, Russia could seek to invade a part of Eastern Europe—given the favorable geography, most likely in the Baltic states—to satisfy its ambitions or to expose the Europeans as weak, thereby positioning itself as Europe’s preeminent power.¹⁵ To be successful, Russian conventional forces would have to quickly overwhelm Baltic defenses while Russian nuclear forces would shield the invasion, forcing Europeans who rush to defend the Baltic states to back down.

In a world where U.S. nuclear forces might no longer serve as a backstop to European security, Russia could conclude that nuclear threats against the rest of Europe could help achieve a military fait accompli. The fact that Russia continues to respect NATO territory as a sanctuary in its war against Ukraine could certainly lead to the conclusion that Russia respects nuclear deterrence, and that Europeans would need nuclear weapons to deter future contingencies in the Baltic states. Yet the bigger takeaway could be that future deterrence in Eastern Europe should focus on conventional forces that make any Russian land grab impossible in the first place.

One scenario that is rarely discussed openly is that Europeans may need their own nuclear deterrent to deter the United States. Trump’s musings that “the world needs us to have Greenland”¹⁶ either through a financial deal or by military force provides the right context to start thinking about the unthinkable.

Since none of the arguments sound entirely plausible, it is possible that Europeans are discussing the nuclear option out of a mix of sheer panic and habit. As an example, Germans have been living under U.S. nuclear protection for some 70 years and successive German governments have chosen regularly to stick to this arrangement.¹⁷ For two decades until 2022, when no one needed U.S. nuclear weapons in Germany, the German public wanted to get rid of these weapons. When Russia invaded Ukraine and threatened Germany, the mood suddenly shifted.¹⁸ Now that Trump is threatening to leave Europe, a majority of Germans want the creation of a European nuclear deterrent.¹⁹ A radical alternative would be for Germans to think about their own security in purely non-nuclear terms. Quite understandably that may be a habitual and psychological stretch too far for most Europeans, particularly in the middle of a major war.

Deterring How?

If the non-nuclear option is too radical, what could a European nuclear deterrent look like? It certainly will not be a supranational EU mechanism but instead will rely on the independent nuclear forces of France and, perhaps, the United Kingdom. Both countries will insist on having the final say, at least when it comes to weapons employment. There would be another no-go as well: Despite Europe’s promised defense spending spree, a European nuclear deterrent will not replicate the U.S. extended deterrence model. Doing so probably would overwhelm European financial resources. The Europeans also are unlikely to seek to match Russian nuclear capabilities. Europe does not need thousands of strategic and tactical nuclear arms. It also cannot afford a full-fledged nuclear sharing arrangement entirely based on non-U.S. assets, at least not now.

Yet, there are steps that Europeans can start taking, such as deepening French-UK cooperation, allowing France regular use of allied European airfields, undertaking explicit public deterrence messaging by prominent European politicians, and perhaps even soliciting financial support from a European coalition of the willing.²⁰ Over the medium term if necessary, France could consider a small increase in its air-delivered munitions and possible French nuclear deployments to other European countries. The UK may think about reinstating its air-delivered nuclear component while seeking more independence from the United States for its nuclear program. All that would give France and the UK more escalation options against Russia and send reassuring signals to jittery allies in Eastern Europe.

Negative Consequences

There are undoubtedly downsides to European nuclear deterrence. It is expensive and will become even more so when extended to others. France just rushed to reopen a fourth nuclear airbase in response to Trump for $1.7 billion.²¹ Paris will soon feel the same pressure that Washington dealt with throughout the Cold War—namely, allies that constantly demand reassurance while never feeling fully reassured. Russia could exploit this effect, pushing Europeans into spending more and more on nuclear arms.

That is why conventional deterrence matters so much. It is the most cost-effective and credible way to contain Russia. It also could have the beneficial effect of bolstering Europe’s defense industry and making Europeans less dependent on U.S. military gear.

Establishing a credible European nuclear deterrent will deliver a severe blow to the global nonproliferation regime. Member states of the nuclear Non-Proliferation Treaty (NPT) would rightfully question whether any move to extend French and UK nuclear deterrence to Europe would be in line with the treaty. Despite the argument brought forward by German legal experts that financial support for French nuclear forces would not violate the NPT,²² politically, any such move could well mean the treaty’s death knell.

For that reason, Europeans would be well advised to complement deterrence with arms control. An arms control track could focus on conventional confidence-building measures along Europe’s long border with Russia and, over the medium term, possible limits on certain kinds of stand-off weapons most prone to cause crisis instability. The biggest obstacle to a purely European arms control approach could be Russia. For many years, the Kremlin has seemed hard-pressed to accept Europeans as independent security actors.

Whether Washington really will turn from protector to predator, and what that could mean for U.S. security guarantees to Europe, including the nuclear ones, remains to be seen. Ultimately, U.S. behavior will decide how far and how fast Europeans may go down the route of nuclear independence. All of this is more than deplorable from a nonproliferation perspective. At some point, however, a European nuclear deterrent could well be seen as the lesser evil. What if the French far right wins the presidential election in two years and declares a “France first” policy? No one should exclude anything at this stage of uncertainty in Europe, including a German or a Polish bomb.

ENDNOTES

1. Jan Cienski and Wojciech Kość, “Poland seeks access to nuclear arms and looks to build half-million-man army,” Politico, March 7, 2025.

2. Chris Lunday, “Europe should brace for Trump to end NATO protection, Germany’s Merz warns,” Politico, February 21, 2025.

3. “France’s Macron is ready to discuss nuclear deterrence for Europe,” Reuters, March 1, 2025.

4. Lauren Sukin, Michal Smetana, Marek Vranka, and Ondrej Rosendorf, “Are the United States and Europe still allies? The European public doesn’t think so,” Bulletin of the Atomic Scientists, March 26, 2025.

5. Julia Mueller, “Trump says he would ‘solve’ war in Ukraine in 24 hours if reelected,” The Hill, March 28, 2023.

6. Tristan Volpe and Ulrich Kühn, “Germany’s Nuclear Education: Why a Few Elites Are Testing a Taboo,” The Washington Quarterly, Vol. 40, No. 3 (2017): pp. 7-27.

7. Lunday, February 21, 2025.

8. Christian Lindner, “Europa muss an nuklearer Abschreckung festhalten [Europe Must Maintain Nuclear Deterrence],” Frankfurter Allgemeine Zeitung, February 13, 2024.

9. Iryna Nesterova, “The last peaceful summer in Europe: a German historian made an alarming prediction – BILD,” Ukraine Today, March 23, 2025.

10. Both arguments have been repeated in the German media for more than a year, for example, including by prominent politicians such as German Defense Minister Boris Pistorius; see Nicolas Camut, “Putin could attack NATO in ‘5 to 8 years,’ German defense minister warns,” Politico, January 19, 2024.

11. Ulrich Kühn, “The Fall Crisis of 2022: why did Russia not use nuclear arms?” Defense & Security Analysis, (2024, ahead of print): pp. 1-21.

12. Janice G. Stein, “Escalation Management in Ukraine: ‘Learning by Doing’ in Response to the ‘Threat that Leaves Something to Chance,’” Texas National Security Review, Vol. 6, No. 3 (2023): pp. 29-50.

13. Todd S. Sechser and Matthew Fuhrmann, Nuclear Weapons and Coercive Diplomacy (Cambridge, UK: Cambridge University Press, 2017).

14. Daniel S. Geller, “Nuclear Weapons, Deterrence, and Crisis Escalation,” Journal of Conflict Resolution, Vol. 34, No. 2 (1990): pp. 291-310.

15. Manuel Bewarder and Florian Flade, “Bereitet Russland einen Angriff auf die NATO vor? [Is Russia Preparing an Attack on NATO?],” Tagesschau, March 27, 2025.

16. David Brennan, “Trump says US will ‘go as far as we have to’ to get control of Greenland,” ABC News, March 27, 2025.

17. Ulrich Kühn, “Of Dependence and Conservatism: Conclusions for German Nuclear Policies in the 21st Century,” in Ulrich Kühn (ed.), Germany and Nuclear Weapons in the 21st Century: Atomic Zeitenwende? (London and New York: Routledge, 2024): pp. 302-314.

18. Michal Onderco, “German Public Opinion on Nuclear Weapons Before and After Russia’s Invasion of Ukraine,” in Kühn, Germany and Nuclear Weapons in the 21st Century, pp. 136-154.

19. Joseph de Weck and Shahin Vallée, “Germans Back Merz’ ‘Whatever It Takes’ on Debt and Defense,” Internationale Politik Quarterly, No. 3 (2025).

20. Héloïse Fayet, Andrew Futter, Ulrich Kühn, Łukasz Kulesa, Paul van Hooft, and Kristin Ven Bruusgaard, “Forum: European Nuclear Deterrence and Donald Trump,” Survival, Vol. 67, No. 1 (2025): pp. 123-142.

21. Laura Kayali, “France to reopen fourth nuclear air base as Europe rushes to rearm,” Politico, March 18, 2025.

May 2025
By Toby Dalton

The about-face on Russia by U.S. President Donald Trump’s administration, amplified by its sharp criticism of the United States’ European allies and apparent abandonment of Ukraine, is scrambling the security order in Europe. Yet, the broader significance of Trump’s embrace of Russian President Vladimir Putin and shift away from enduring interest-based alliances is that these moves also could portend considerable disruption in Asia. Some of that disruption might be positive, for example if it leads to arms control talks with China or a nuclear restraint agreement with North Korea. Yet, it also could drive South Korea or Japan to acquire nuclear weapons if they feel abandoned by the United States.

Russia vs. China

Trump’s shift toward Russia reads like a classic great-power politics gambit: an attempt to ameliorate conflict between Washington and Moscow that otherwise keeps the United States tied to Europe, and to woo Russia over to the U.S. side against China.

The biggest unknown is whether Putin sees the situation reciprocally. In recent years, Russia pursued a comprehensive strategic relationship with China, what the two countries have labeled a “no limits” partnership.¹ In the three years since Russia’s full-scale invasion of Ukraine, Beijing and Moscow have deepened their military ties and now regularly conduct combined exercises. China has been a steadfast although primarily rhetorical supporter of Russia’s war in Ukraine, and the two countries are aligned in challenging or subverting a U.S.-led international order. Broadly, the ideological divisions and divergent interests that contributed to the Sino-Soviet split in the 1960s are not present today and it seems doubtful that the United States could easily drive China and Russia apart.

If creating a wedge between China and Russia proves impossible, Trump may instead seek Putin’s help to engage Chinese President Xi Jinping in nuclear talks. Although perhaps not as strong as his obsession with striking a nuclear deal with North Korea, Trump periodically floats the idea of China joining Russia-U.S. nuclear arms control negotiations. He stated March 6, “I was very close to having a program with Russia—denuclearization—and we were going to get China; I spoke with President Xi about it, and he would have been very happy to go along with it.… But I would very much like to start those talks … the denuclearization would be incredible.”²

Despite Trump’s bromides, China’s consistent position on joining arms control negotiations effectively can be summarized as “No thanks; you first make deeper cuts and then we might consider it.”³ Yet, a Russia-U.S. rapprochement that facilitates a successor to the New Strategic Arms Reduction Treaty eventually could enable three-way talks with China. Although it is difficult today to imagine such an agreement to limit or even reduce nuclear arms, there are many other avenues for reducing the chances of nuclear use that would be beneficial for U.S. and global security.

Russia, North Korea, and Nuclear Talks

To help prosecute its war in Ukraine, Russia revamped its military relationships with North Korea and Iran. Initially, this involved buying Iranian-made kamikaze drones and North Korean artillery shells. Later, North Korea provided short-range ballistic missiles and even 11,000 soldiers to fight directly alongside Russian forces seeking to expel Ukrainian forces from occupied territory in Russia’s Kursk region. North Korea and Russia signed a new mutual defense pact in June 2024.

The quid pro quos for this military assistance to Russia are not fully clear, although Russia promised to cooperate on space and peaceful nuclear energy with North Korea as part of upgraded military ties. More broadly, analysts have interpreted Russia’s embrace of both countries—North Korea has tested a nuclear weapon and Iran is moving closer to being able to produce a bomb—as indicating abandonment of nonproliferation as a long-standing strategic priority. U.S. officials warned in December 2024, for example, that “Russia may be close to accepting North Korea’s nuclear weapons program, reversing Moscow’s decades-long commitment to denuclearize the Korean peninsula.”⁴

How Russia treats these partnerships in the future could be a critical factor as Trump seeks to forge a broader rapprochement with Putin, and also to constrain the nuclear programs of Iran and North Korea. Does Putin see them as transient relationships of convenience in the context of Ukraine or as building blocks of Russia’s effort to reconstitute its global power?

To that point, in a March 18 telephone call that raised more questions than answers, Trump and Putin reportedly agreed on “the need to stop proliferation of strategic weapons and [to] engage with others to ensure the broadest possible application.”⁵

North Korea poses the most challenging issues in this regard. Trump regularly expresses interest in rekindling efforts to reach a nuclear deal with North Korean leader Kim Jong Un, as he did March 13, saying, “I have a great relationship with Kim Jong Un, and we’ll see what happens, but certainly he’s a nuclear power.”⁶ North Korea’s nuclear weapons arsenal has indeed grown in number and sophistication since Trump failed to close a restraint agreement with Kim during their summit diplomacy in 2018-2019. These advanced North Korean capabilities are among the drivers of South Korean interest in nuclear weapons, so a restraint agreement with Pyongyang could also dampen nuclear clambering in Seoul.

As with Xi, Putin might be tempted to parlay Trump’s desire for a nuclear deal with Kim for a seat at the negotiating table and influence on the outcome. Undoubtedly, Putin would want to ensure that any North Korean-U.S. engagement does not compromise Russian interests, but he also may calculate that helping Trump could yield dividends elsewhere.

Conversely, North Korea may be perceived in Russia as a useful thorn in the side of the United States and its Asian allies. Russian national security expert Dmitry Trenin argued in 2023, for example, that, “destabilization of the [nuclear Nonproliferation Treaty] is an important factor undermining American hegemony.… [T]he DPRK and Iran are political opponents of the United States and at the same time increasingly close partners of Russia. It is unthinkable to cooperate with Washington, which is waging a war with Russia by the hands of Ukrainians, against Iran and the DPRK, which somehow help [sic] us in this war.”⁷

Impact on Japan and South Korea

Thus far, Japan and South Korea have been spared the ire of Trump administration officials, who mainly have criticized European governments for various perceived offenses. But Seoul and Tokyo no doubt are discomfited by Trump’s intimations that he may not feel bound by long-standing U.S. security guarantees. During the 2024 presidential campaign, for instance, Trump famously recounted a conversation with a foreign head of government in which he said he “would not protect you. In fact, I would encourage [Russia] to do whatever the hell they want. You gotta pay.”⁸ In this regard, Trump’s abusive abandonment of Ukraine could spur additional efforts to augment security capabilities, including consideration of nuclear weapons, among U.S. Asian allies. South Koreans, in particular, have long harbored fear about U.S. abandonment dating to the 1949 withdrawal of U.S. military personnel, followed shortly thereafter by the North Korean invasion that catalyzed the 1950-1953 Korean War.

In Seoul, there has been growing interest in and public support for nuclear weapons for over a decade, well before Trump was even a likely political candidate. South Korean political conservatives are the most vocal champions of a domestic nuclear weapons program, but Trump’s behavior may give progressives reason to reconsider their skepticism. For now, there is a growing movement for nuclear “latency” (called the Mugunghwa Forum), whereby South Korea would accumulate the additional capabilities necessary for producing nuclear weapons should it decide to build them in the future.⁹

Nuclear latency advocates are urging the South Korean government to negotiate with the United States for permission to develop uranium enrichment and plutonium reprocessing capabilities, first by upgrading the existing South Korean-U.S. nuclear cooperation agreement. This is highly likely to be a key item on Seoul’s wish list as South Korean and U.S. officials sort through alliance, security, and trade issues.

The real wild card pertains to the Trump administration’s intentions regarding the U.S. defense posture and extended deterrence commitments. If Trump seeks to withdraw U.S. forces stationed on the Korean peninsula, then South Korean leaders might feel forced to proceed with a nuclear weapons effort, despite the challenges they would likely encounter.

Japan in many ways occupies a more difficult position: With a capable but constrained self-defense force, it is more reliant on U.S. extended deterrence despite its security and territorial issues with China, North Korea, and Russia. Tokyo has fewer immediate options to remedy U.S. retrenchment, apart from building nuclear weapons, which it likely could achieve faster than South Korea but which would be far more politically complicated given the strong Japanese pro-disarmament movement. Tokyo seems likely to continue efforts to stay out of Trump’s firing line and not give him any reason to consider abandonment.

As the implications of Trump’s shift toward Russia become clear, the potential effects in Asia seem likely to boil down to the issue of linkage. In the past, Russia has proved willing to use its influence to further nonproliferation goals, as it did during negotiations with Iran leading to the 2015 nuclear agreement. However, if transactional politics dominate in the absence of a broader Russian-U.S. strategic alignment, Moscow will be less willing to use its influence with China or North Korea in ways that could benefit the United States.¹⁰ At least, not without extracting a price. Whether that price includes a reduction in the U.S. defense posture in Asia, negotiated without the input of U.S. allies, will be a critical determinant of the future number of nuclear-armed states in the region.

ENDNOTES

1. “Joint Statement of the Russian Federation and the People’s Republic of China on the International Relations Entering a New Era and the Global Sustainable Development,” President of Russia, February 4, 2022.

2. @RapidResponse47, Remarks by U.S. President Donald Trump, X, March 6, 2025, 3:13 PM.

3. “Foreign Ministry Spokesperson Guo Jiakun’s Regular Press Conference on February 14, 2025,” Ministry of Foreign Affairs of the People’s Republic of China, February 14, 2025.

4. “Remarks by Ambassador Linda Thomas-Greenfield at a UN Security Council Briefing on Nonproliferation and the Democratic People’s Republic of Korea,” United States Mission to the United Nations, December 18, 2024.

5. White House Press Secretary Karoline Leavitt, “President Donald J. Trump’s Call with President Vladimir Putin,” U.S. Embassy & Consulates in Russia, March 18, 2025.

6. “Trump says he still has good relations with leader of ‘nuclear power’ North Korea,” Reuters, March 13, 2025.

7. Dmitry Trenin, “On a New Global Order and Its Nuclear Dimension. An Interview,” PIR Center, 2023, No. 2: 36, 2023.

8. Jill Colvin, “Trump says he once told a NATO ally to pay its share or he’d ‘encourage’ Russia to do what it wanted,” Associated Press, February 11, 2024.

9. Lami Kim, “South Korea’s Nuclear Latency Dilemma,” War on the Rocks, September 19, 2024.

10. Keith Bradsher and Berry Wang, “China Backs Iran in Nuclear Talks, Slams ‘Threat of Force’ From the West,” The New York Times, March 14, 2025.

May 2025
By Kelsey Davenport

The United States and Iran began discussions on a nuclear agreement, but Trump administration officials have sent mixed messages about U.S. objectives for a deal. Specifically, it is unclear if the United States will accept an agreement that allows Iran to continue to enrich uranium, an issue that Iran says is non-negotiable.

President Donald Trump told reporters that the United States and Iran would begin negotiations in Oman the following week during an April 6 meeting with Israeli Prime Minister Benjamin Netanyahu. The New York Times reported on April 16 that Trump told Netanyahu during the meeting that the United States would not support Israeli plans to strike Iran’s nuclear program in May. Trump told reporters on April 17 that he is not “in a rush” to attack and that Iran is “wanting to talk.”

Although both Trump and Iranian President Masoud Pezeshkian have expressed support for a nuclear deal, it is unclear if the two sides will be able to bridge the gaps and reach an agreement. Netanyahu also appears unlikely to support an agreement. He released a video statement on April 7 suggesting that Israel would support diplomacy with Iran, but an effective agreement must include completely dismantling Iran’s nuclear program under U.S. supervision.

The United States and Iran described the first meeting between U.S. Special Envoy to the Middle East Steve Witkoff and Iranian Foreign Minister Abbas Araghchi as constructive. Although the talks were indirect, Araghchi and Witkoff shook hands and spoke briefly.

After the meeting, Witkoff told Fox News April 14 that Iran could enrich uranium up to 3.67 percent uranium-235, a level suitable for nuclear reactor fuel. He also said a deal would focus on monitoring and prohibiting weaponization-related activities. The following day, however, Witkoff said on X that Iran must “eliminate its nuclear enrichment and weaponization program.”

Other senior Trump administration officials, including Secretary of State Marco Rubio and National Security Advisor Michael Waltz, also suggested Iran must give up uranium enrichment as part of an agreement.

Araghchi told Iranian media April 16 that the shifting U.S. position is “not helpful,” but he said Iran will look to the United States to make clear its “real position” during talks.

He said Iran’s nuclear enrichment program is intended to fuel nuclear power reactors and that Iran is willing to “build trust regarding potential concerns but the issue of enrichment is non-negotiable.”

In a transcript of a speech Araghchi intended to deliver April 21, he elaborated on Iran’s position, saying Tehran is “ready to engage” with Washington, but the basis for talks must include a “recognition of our rights” under the nuclear Nonproliferation Treaty (NPT), “including the ability to produce fuel for our nuclear power plants.”

The United States disagrees that the provision in the NPT that guarantees non-nuclear-weapon states access to nuclear technology under appropriate safeguards for peaceful purposes includes a right to enrich. However, the Obama administration’s acknowledgement that Iran could retain a limited uranium enrichment program was critical for advancing negotiations toward the interim nuclear deal in 2013 and later the 2015 deal, known as the Joint Comprehensive Plan of Action (JCPOA).

Under the JCPOA, Iran agreed to limit its uranium enrichment to a level suitable for reactor grades, 3.67 percent of U-235, the level Witkoff initially suggested the United States could support in a new deal.

Currently, Iran is enriching uranium up to 60 percent, U-235. Sixty percent enriched uranium is near-weapons grade and has no legitimate civilian purpose in Iran’s program.

Despite Witkoff backpedaling on the issue of uranium enrichment, Araghchi said the two parties moved forward during the second round of talks in Rome on April 19 and have a “better understanding of the goals.” He said that Iran is “seeking an agreement as quickly as possible” but noted it will not be easy.

Trump told reporters on Air Force One April 12 that the talks were going “okay” but “nothing matters until you get it done.”

International Atomic Energy Agency Director-General Rafael Mariano Grossi stressed the short timeframe available for talks during an April 15-16 meeting in Tehran. Grossi told reporters April 17 that IAEA verification of any deal is necessary to ensure its validity. He said the IAEA is in contact with the U.S. negotiating team to see how the agency can “help achieve a positive outcome in the negotiations.”

The IAEA has raised concerns in its quarterly reports on Iran’s nuclear program about the challenges of reconstituting credible baseline inventories in certain areas, such as centrifuges, since Iran reduced agency access and monitoring in February 2021.

Grossi said during the second round of talks in Rome in an April 19 X post that cooperation with the IAEA is “indispensable to provide credible assurances about the peaceful nature of Iran’s nuclear programme.”

May 2025
By Xiaodon Liang

U.S. generals are calling for an increase in the number of B-21 nuclear-capable strategic bombers that the United States will buy, lauding the aircraft as a rare on-time and under-budget component of an otherwise increasingly troubled nuclear modernization program.

The Air Force should acquire 145 B-21s instead of a planned 100, said Gen. Anthony J. Cotton, head of U.S. Strategic Command, March 18 at an industry conference. Although he and other commanders have hinted previously at recommending an increase to the B-21 program, this was the first time Cotton has explicitly endorsed a higher target. He repeated the recommendation at a March 26 hearing before the Senate Armed Services Subcommittee on Strategic Forces.

Cotton also reiterated a prior call for an acceleration of the B-21 program, which is in low-rate initial production under the supervision of lead contractor Northrop Grumman. The chief executive of the company, Kathy Warden, said on  a call April 22 that the firm had already made investments to prepare to speed up production rates, bringing company losses on the bomber to an expected $2 billion over the first five years of production.

The House Armed Services Committee voted April 29 to provide $4.5 billion over the next four years to accelerate B-21 production, as part of a broader budget reconciliation bill.

In an exchange with Senator Mike Rounds (R-S.D.) during the March 26 hearing, Cotton said he was concerned about a significant temporary shortfall—a “bathtub” plunge—in the availability of strategic bombers as the B-2 and B-1 fleets age and retire.

Cotton’s recommendation is backed by some high-ranking Air Force officers. The “demand signal for the bombers is greater than any time I’ve seen in my career,” said Gen. Thomas A. Bussiere, head of Air Force Global Strike Command, at a Dec. 5 Mitchell Institute event.

But other Air Force leaders have been more cautious. A year ago, the service’s chief of staff, Gen. David W. Allvin, declined before the Senate Armed Services Committee to commit to an expansion of the program, noting that available technologies may have changed by the time the planned 100-aircraft production run is completed in the mid-2030s.

President Donald Trump’s nominee to serve as secretary of the Air Force, Troy Meink, suggested openness to reassessing the bomber requirement during his March 27 confirmation hearing before the same Senate committee. The Air Force fleet is “probably too small both on the fighter and the bomber sides of the house,” Meink said.

The B-21 program is “a successful acquisition program by all accounts,” according to Michael Duffey, the nominee for undersecretary of defense for acquisition and sustainment, as he testified alongside Meink March 27.

Duffey’s optimistic view is supported by price estimates published in November 2024 by Aviation Week & Space Technology, which said that the cost to the Air Force of the initial five-years of production has fallen 28 percent from $19.1 billion, as estimated in fiscal year 2023, to $13.8 billion in fiscal 2025. The Defense Department withholds more budgetary and programmatic information about the B-21 than most components of the nuclear modernization effort.

Northrop Grumman received its second year-long, low-rate initial production contract in December. Over the first five contracts, the company is set to build 21 initial aircraft under a fixed-price-plus-incentive reimbursement framework (See ACT, January/February 2025.)

The nuclear-tipped, air-launched cruise missile that the B-21 will deliver, the Long Range Stand Off Weapon, underwent a first flight test in January with its W80-4 warhead, which is in development, according to the Exchange Monitor. The W80-4 program has struggled recently with design issues that could impact its production schedule, according to a January performance evaluation report by the National Nuclear Security Administration, which reviewed work by a key contractor at Lawrence Livermore National Laboratories.

The W80-4 program leadership needs a “focused and disciplined approach” to “avoid program schedule impacts” for the warhead, the evaluation report said.

New delays also are affecting Air Force programs to upgrade the aging B-52H strategic bomber to a new B-52J configuration. According to the annual report of the Pentagon’s director of operational test and evaluation, released in January, the B-52 radar modernization program will now enter production in fiscal 2026 at the earliest. A parallel program to replace the planes’ engines will reach an equivalent milestone in fiscal 2029.

The relative success of the B-21 program stands in contrast to continuing problems with the Columbia ballistic missile submarine and the Sentinel intercontinental ballistic missile (ICBM).

The lead ship of the Columbia class is now 12 to 18 months behind schedule, Navy acquisition leaders said in an April 8 statement to the Senate Armed Services Subcommittee on Seapower and Projection Forces. Work on the second boat of the class remains on schedule, the statement says.

Navy efforts to attract more skilled labor to shipyards have had mixed results, with between 50 and 60 percent of new employees leaving their jobs within the first year, said Brett Seidle, the acting assistant secretary of the Navy for research, development, and acquisition, before the same subcommittee March 26.

As the Air Force reevaluates the scope of the Sentinel ICBM program following a Nunn-McCurdy cost-growth review last year, officials also are weighing the steps needed to keep the Minuteman III ICBM in service through 2050, Bloomberg News reported March 27. The Sentinel is now expected to enter service several years after its target date of 2029. (See ACT, September 2024.)

May 2025
By Xiaodon Liang

U.S. President Donald Trump’s nominee to head the National Nuclear Security Administration (NNSA) said he “would not advise testing” nuclear weapons above the criticality threshold.

But the nominee to be administrator, Brandon Williams, testifying at his April 8 Senate Armed Services Committee confirmation hearing, also noted that a decision to resume explosive nuclear testing would be “above [his] pay grade.”

Williams’ comments came in response to questioning by Sen. Jacky Rosen (D-Nev.), who expressed concern that resuming explosive nuclear testing could create “severe economic and environmental impacts.” The Nevada National Security Site, where NNSA conducts subcritical nuclear experiments, almost certainly would host any potential underground explosive test.

Rosen said China and Russia would probably resume explosive nuclear testing if the United States were to test first, and those countries “have more to gain from testing than we do, given our superior scientific and computer-modeling capabilities.”

Williams, a former Navy ballistic-missile submariner and Republican congressman, agreed that explosive testing during the Cold War had provided data to underpin the “scientific basis for confirming the stockpile since the moratorium in 1992.”

Scott Pappano, a Navy vice-admiral nominated to be Williams’ principal deputy at NNSA, also told the same Senate committee April 29 that he “would not advocate for nuclear testing based on the amount of data we have.”

Concerns about a resumption of testing have grown since Robert O’Brien, a national security advisor in Trump’s first term in office, wrote in Foreign Affairs in June that “Washington must test new nuclear weapons for reliability and safety in the real world for the first time since 1992—not just by using computer models.”

During O’Brien’s government tenure, a group of U.S. officials discussed testing in May 2020, according to a report in the Washington Post. (See ACT, June 2020.)

The technical need for testing has been dismissed by officials involved in the U.S. stockpile stewardship program. Marvin Adams, the deputy administrator for defense programs at NNSA under the Biden administration, told reporters on a tour of the Nevada National Security Site Dec. 13 that “based on purely technical considerations, we are confident that we can get the information we need [through] subcritical” experiments and other elements of the stockpile stewardship program.

The 2020 debate considered not only technical arguments, however, but also policy justifications such as intimidating nuclear peers during arms control talks.

A report by the Trump-aligned Heritage Foundation in July called for reducing the time needed to prepare an underground explosive nuclear test to six months. Under a requirement last reaffirmed in 2022 by the Biden administration, the NNSA is required to be ready to conduct a test with limited diagnostics within 36 months.

In September, Russian Deputy Foreign Minister Sergey Ryabkov told news agencies that Russia “will not conduct [supercritical nuclear tests] if the United States refrains from such steps.”

May 2025
By Kelsey Davenport

U.S. President Donald Trump said the United States is communicating with North Korea but did not provide any details regarding his administration’s approach to addressing the nuclear threat posed by Pyongyang. Meanwhile, North Korea continues to justify expanding its nuclear arsenal as a necessary counter to the threat posed by the United States.

In a March 31 remark to a reporter at the White House, Trump described North Korea as a “big nuclear nation” and emphasized his “very good relationship” with North Korean leader Kim Jong Un. Trump said he will “probably do something with him at some point.”

Trump and Kim met three times during Trump’s first term as president. At their first meeting in Singapore, Trump and Kim signed a declaration that included a commitment to the denuclearization of the Korean peninsula and to establishing a new relationship between the United States and North Korea. (See ACT, July/August 2018.)

The declaration produced few tangible results, and since then, Kim has expanded North Korea’s nuclear arsenal and broadened the circumstances under which Pyongyang would consider using nuclear weapons.

Although the Trump administration has reaffirmed its commitment to denuclearization, North Korea now rejects that goal, and it is unclear if Pyongyang would be willing to engage Washington if denuclearization remains the goal.

In an April 9 statement to the state-run Korean Central News Agency, Kim Yo Jong, the sister of Kim Jong Un, said that denuclearization is an “anachronistic” goal and U.S. insistence on it only gives “unlimited justness and justification” for North Korea “building the strongest nuclear force for self-defense.”

North Korea’s nuclear weapon status can “never be reversed by any physical strength or sly artifice,” she said.

Although Trump’s remarks suggested that his administration is not currently prioritizing North Korea, Gen. Dan Caine, the chairman of the Joint Chiefs of Staff, said that “North Korea’s long-range missile and nuclear programs pose an immediate security challenge” to the United States.

Caine, in his confirmation testimony before the Senate Armed Services Committee April 1, warned that North Korea’s relationship with Russia will likely enable further military advances, “increasing the threat to regional stability and U.S. interests.”

Although there does not appear to be an immediate opening for diplomacy with North Korea, the upcoming presidential election in South Korea could lower tensions on the Korean peninsula. Because the South Korean Supreme Court upheld the impeachment of President Yoon Suk Yeol over his declaration of martial law last year, the country must hold elections by June 3.

When Yoon took office in 2022, he pledged to build up South Korea’s military and take a harder line on North Korea than his predecessor, Moon Jae-in, who facilitated the first meeting between Trump and Kim in 2018. The next government may pursue a less adversarial approach toward North Korea to ease tensions. It may also distance itself from calls for South Korea to develop nuclear weapons, which senior officials discussed more prominently during the Yoon administration, prompting backlash in the United States. (See ACT, March 2023.)

In March, the U.S. Department of Energy designated South Korea as a “sensitive” country, which will subject foreign nationals to more stringent review and to an approval process on cooperative projects. Concern about nuclear proliferation is one of the reasons a given country is designated sensitive.

Other countries on the “sensitive” list include China, Iran, Israel, Russia, and Taiwan.

South Korean officials downplayed the designation, which went into effect April 15, and suggested it has nothing to do with concerns that Seoul might pursue nuclear weapons. They emphasized that the country does not face any new restrictions on access to cooperative projects.

South Korean Foreign Minister Cho Tae-yul said March 24 that the United States told South Korea that the decision was part of an effort to strengthen technical security and protect intellectual property.

May 2025
By Daryl G. Kimball

Since Russia and the United States agreed 15 years ago to modest nuclear reductions under the New Strategic Arms Reduction Treaty (New START), they also have embarked on extraordinarily expensive campaigns to replace and modernize every component of their respective nuclear arsenals to maintain force levels and provide the option to build up.

At the same time, their leaders have failed to resolve disputes about existing treaties or launch new negotiations to limit or further cut their deadly arsenals below the New START ceiling of 1,550 deployed nuclear warheads and 700 strategic missiles and bombers each.

In 2018, shortly after he withdrew the United States from the Intermediate-Range Nuclear Forces Treaty, U.S. President Donald Trump foolishly bragged about the nuclear stockpile that “until people come to their senses, we will build it up. It’s a threat to whoever you want, and it includes China, and it includes Russia, and it includes anybody else that wants to play that game.”

China has responded to U.S. nuclear and conventional military plans by pursuing a buildup of its historically “minimal” nuclear force to ensure that it retains an assured “second strike” capability. Russia has continued to develop new types of intermediate range missiles, as well as some new and exotic strategic systems designed to bypass U.S. missile defense capabilities.

Successive presidential administrations and congresses have failed to seriously consider alternatives that would have reduced costs and still maintained a devastating nuclear force.

Now, the cost of the U.S. nuclear modernization program is skyrocketing even further, siphoning resources from other more pressing human needs and national security priorities.

In April, the Congressional Budget Office issued its latest 10-year cost projection of the departments of Defense and Energy plans to operate, sustain, and modernize existing U.S. nuclear forces and purchase new forces: a total of $946 billion in the 2025-2034 period, or about $95 billion per year.

This new estimate is 25 percent, or $190 billion, greater than the last CBO estimate of $756 billion, which covered the 2023-2032 period. Incredibly, the $946 billion estimate does not include all of the likely cost growth of the new Sentinel intercontinental ballistic missile program, which the Pentagon acknowledged in July 2024 would cost 81 percent, or $63 billion, more than the program’s baseline estimate of $78 billion, generated in 2020.

A decade ago, Air Force leaders ignored the results of a 2014 RAND study, commissioned by the service itself, which found that “incremental modernization and sustainment of the current Minuteman III force is a cost-effective alternative that should be considered.” In 2021, the Pentagon decided to ignore a request from 20 Democrats in Congress for an in-depth analysis of whether the existing Minuteman III force, which the Sentinel would replace, could be fielded further into the future.

In the wake of the Sentinel program fiasco, the Pentagon is now looking into extending portions of the Minuteman III force for another decade to 2050 while it restructures the Sentinel program, making the full extent of the cost growth unclear.

What is clear: Building up the U.S. nuclear force beyond New START levels—as Trump threatened in his first term and as some nuclear weapons boosters are advising now—would not only be unnecessary to deter a Russian or Chinese nuclear attack, it would be even more costly. It also would further strain the ability of the U.S. nuclear enterprise to maintain the existing force on schedule and on budget.

Yet, absent a new U.S.-Russia deal to maintain current limits on their strategic nuclear arsenals, a dangerous three-way arms race looms. Perhaps this is why Trump has spoken three times since his January inauguration about the massive costs of nuclear weapons, the catastrophic effects of their use, and his interest in talks with China and Russia to “denuclearize.”

But with New START due to expire in less than a year, there are still no talks underway on whether or how to replace the treaty. Although Russian officials say they are ready to engage, Trump has not outlined a strategy for getting the job done.

U.S.-Russian nuclear arms control negotiations always have been difficult. Achieving a new comprehensive framework could require sustained talks over many months, if not longer.

The smartest approach would be for Russian President Vladimir Putin and Trump to strike a simple, informal deal to maintain the existing caps set by New START as long as the other side also does so. They could agree to resume data exchanges and inspections, or should that not be feasible, monitor compliance through national technical means of intelligence.

Such a deal would reduce tensions, forestall a costly arms race on long-range nuclear missiles that no one can win, and buy time for talks on a broader, more durable, framework deal while also forgoing calls in Congress to throw away billions of dollars more on the already unaffordable and excessive U.S. nuclear arsenal.

May 2025
By Shizuka Kuramitsu

Against a backdrop of rising nuclear proliferation concerns, states-parties to the nuclear Nonproliferation Treaty (NPT) are holding their last meeting to prepare for the 2026 Review Conference, which aims to strengthen the landmark pact.

The third and final NPT preparatory committee meeting began April 28 in New York and plans to wrap up May 9.

The 191 states-parties to the cornerstone NPT, which enshrines key commitments on nonproliferation, disarmament, and peaceful uses of nuclear energy, are supposed to “make every effort to produce a consensus report containing recommendations” to the forthcoming review conference, as the 2000 Review Conference directed.

The meeting is taking place when the international political climate is posing significant challenges to the global disarmament and nonproliferation regime. In addition to long-term issues with the Iranian and North Korean nuclear programs, there are growing concerns about weakening U.S. commitments to allied defenses, including France, Germany, and Poland, under President Donald Trump. (See ACT, April 2025.)

The 2026 Review Conference dates are not set but the New Strategic Arms Reduction Treaty, the last remaining treaty limiting the Russian and U.S. nuclear arsenals, expires Feb. 5, 2026. In January, Trump signaled interest in addressing denuclearization issues with China and Russia, but no major follow-up has been reported. (See ACT, March 2025.)

“There is a need for high-level political leadership to ensure that the risk is brought down. And [Trump’s] indication of a willingness to be able to engage in that direction is one that I find encouraging,” Harold Agyeman of Ghana, chair of the 2025 preparatory committee meeting, told Arms Control Today in an interview March 19.

“I hope that we can leverage that to engage in discussions, including on the suspension of the New Strategic Arms Reduction Treaty by the Russian Federation, and look beyond 2026 in terms of what will be done by these two major nuclear-weapon states,” Agyeman said.

Participants in the NPT review process have long considered the ideal outcome of preparatory committee meetings to be a formal consensus agreement on the draft rules of procedure, a provisional agenda, a formal summary by the meeting chair, and recommendations for the review conference.

Notwithstanding, no meeting since 2002 has adopted a chair’s factual summary by consensus.

Instead, chairs typically have issued factual summaries as working papers on their own authority, to document what states discussed during the meeting and to serve as a blueprint for further discussion.

Because forming a consensus at NPT meetings has been a chronic challenge, divisions among states-parties have deepened. The past two preparatory committee meetings concluded with unprecedented endings. No official chair’s summary was recorded in 2023 due to Iran’s objection, and in 2024, a Russian proposed footnote decreed that the chair’s summary “shall not be considered as a basis for future work within the NPT review process.” (See ACT, September 2024.)

“There are a lot of pressures on the treaty, from outside the treaty’s realm, but also from the inside,” Jarmo Viinanen of Finland, who chaired the 2023 preparatory committee, noted in the Arms Control Today interview March 19.

“At the same time, when we are approaching the review conference next year, we can see that the turmoil that we are facing in today’s world actually makes all the purposes of the treaty even more urgent and important,” Viinanen said.

“It is clear that in this very difficult situation, we need more nuclear disarmament than ever before,” he added.

May 2025
By Mina Rozei

More than 100 chemical weapons sites associated with ousted Syrian President Bashar al-Assad’s regime are believed to remain in Syria, a far higher number than previously estimated, according to the Organisation for the Prohibition of Chemical Weapons (OPCW).

The new estimate was first reported by The New York Times April 5 and confirmed for Arms Control Today by OPCW Director-General Fernando Arias in an email exchange April 18.

Arias said that the estimated number of sites is based on a combination of the Syrian government’s own declaration when it joined the OPCW in 2013; the work of the OPCW Declaration Assessment Team, which is composed of investigation experts, information from OPCW member states; and information from the interim Syrian government that took office when Assad fled Syria in December.

“It is the correlation and analysis of all this information that allowed the Secretariat to consider that more than 100 locations in Syria need to be visited,” he told Arms Control Today.

Arias said that the “inaccurate and incomplete” nature of Syria’s initial declaration, which detailed more than 40 years of Syrian chemical weapons development and stockpiling, has been a major stumbling block over the last 10 years as the OPCW attempted to address the remaining stockpile.

The current transitional government in Damascus appears to be taking a more open and transparent approach to the issue, even declaring its disapproval of the Assad regime’s use of chemical weapons. (See ACT, April 2025.)

Syrian Foreign Minister Asaad al-Shaibani has been working closely with the OPCW at the invitation of Arias, who invited the minister to appoint experts to discuss the Syrian chemical weapons program in full, including parts that had not been declared by the Assad government. “I informed the minister that the [OPCW Technical] Secretariat was ready to deploy and shared a roadmap we had developed to work together to establish an inventory of all that needs to be declared and verified,” Arias said.

Arias met Syria’s transitional president, Ahmed al-Sharaa, and Shaibani in Damascus and characterized the meetings as an opportunity to “exchange points of view and information in detail in a sincere and open manner and in a constructive atmosphere.... During these visits we have found goodwill and active cooperation on the Syrian side.”

He emphasized that with the cooperation of the current transitional Syrian government, there is a renewed push to finally eliminate the Syrian chemical weapons program and close the file. The OPCW and the Syrian government are working in tandem to hold accountable those responsible for past chemical attacks. Arias said that the OPCW is sharing its expertise to support Syria’s capacity building and knowledge in case of future attacks, perhaps alluding to the insecurity of the remaining stockpile.

Arias sees this renewed cooperation as a turning point in the work of the OPCW and stressed that Sharaa “mentioned that he wanted Syria to become a positive example for the region and the world in dealing with chemical weapons and their tragic and lasting footprint in this country.”

“We know that we will have to overcome many obstacles, but we also know that we can and will count on the support of the new authorities,” he said.