Nuclear weapons could spread to more countries than at any point since the Cold War. The US has positioned itself as much more open to enrichment in new countries, and Europe is questioning whether it can still count on American protection.
Nuclear proliferation–or the spread of nuclear weapons, fissile material, or linked technology–is accelerating under the Trump administration, with the nuclear club potentially set to expand in the coming years. Since 2006, when North Korea acquired the bomb, the number of countries with domestic nuclear weapons programs has remained the same. Iran has been teetering towards a nuclear weapons program for decades, with the US waging a war–at least in part–over its pursuit of the bomb. After decades of attempting to prevent the spread of nuclear weapons, the current US administration is now taking steps to reduce the barriers to nuclear technology, which could lead to an increase in the number of countries with access to this dangerous technology. The Trump administration–alternating between threatening violence against Iran for pursuing nuclear weapons and then offering to negotiate–is actively contributing to the erosion of norms of nuclear proliferation and, as a result, more countries might turn to nuclear weapons as a safeguard.
The Trump administration’s controversial policy of “friendly” proliferation–encouraging the spread of nuclear weapons with close regional allies to counter mutual adversaries–is setting two countries, South Korea and Saudi Arabia, on an expedited path towards developing nuclear weapons. Last November, the Trump administration announced the United States would support South Korea’s civilian uranium enrichment. Then, in July, it was announced that the United States will support Saudi Arabia’s civilian nuclear energy. These two steps show the seriousness and willingness of the United States under Trump to further lower the barrier for entry to nuclear technology. Offering US technology and support for enriching uranium for South Korea and Saudi Arabia–two countries that have expressed interest in developing nuclear weapons in the past–risks a cavalcade of other countries seeking to hedge against an increasingly isolationist United States that demands more of allies, while simultaneously casting doubts over international treaty commitments.
Meanwhile, Europe is assessing its security needs–both conventional and nuclear–in light of warnings of a potential Russian attack on NATO territory within the next few years and amidst an escalating campaign of shadow warfare from Russia. The US “friendly” proliferation policy has profound implications for Europe's nuclear deterrence options, given concerns it may no longer be able to rely on the United States’ nuclear umbrella. Europe’s nuclear deterrence stance has shifted as a result, including greater UK-France cooperation, talk of creating an independent European deterrent, France’s enhanced “forward deterrence” doctrine, and even the Nordic countries developing their own nuclear weapons. Germany’s only uranium enrichment plant is–at the request of the UK government–taking steps to begin to produce “reactor fuel” for defense purposes. With few guardrails limiting the build-up of nuclear weapons, a US administration nudging allies to develop their domestic nuclear weapons program, and multiple global conflicts, the risks of nuclear conflict are increasing. A cascade of nuclear proliferation could irrevocably alter power balances in volatile regions, lead to less transparency or predictability in nuclear weapons build-ups, ultimately leading to more deadly conflicts with longer lasting scars.
Nuclear Disarmament at an Impasse
At midnight on February 4, the New Strategic Arms Reduction Treaty (New START) limiting the stockpiles of the two largest nuclear powers–Russia and the United States–expired without a replacement negotiated. In the absence of a new deal, an uneasy stalemate has emerged between the two countries, with neither seeking to trigger another nuclear arms race. In the context of this breakdown in nuclear disarmament, “friendly” proliferation risks upsetting the delicate balance between the United States and Russia, while further encouraging China to develop its rapidly expanding nuclear weapons program unchecked.
Although New START was far from perfect–with criticism ranging from widely accepted claims of Russia not adhering to the treaty to the Trump administration’s reversal of an Obama administration policy to not develop new nuclear warheads–the treaty provided some framework for discussion and mutually agreed upon baselines. The willingness of Russia and the United States to agree to curb their nuclear weapon programs now seems to be a relic from a bygone era, as further reflected in the multi-year failure to achieve a consensus of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT).
As the deadline for extending New START loomed, Russian President Vladimir Putin offered to extend the limits of the treaty for another year in a rare showing of magnanimity. This offer was not accepted by the United States, which chose to let New START lapse. According to President Trump, the United States will instead seek a “new, improved, and modernized Treaty that can last long into the future.” Despite this claim, no public progress has been made in negotiating an alternative or successor deal to New START and it is unclear if it is even possible to negotiate on this topic, given more pressing global events. The US-Israeli conflict with Iran has taken up much of the administration’s bandwidth since New START expired. This has even sidelined negotiations with Russia over ending its illegal war of aggression against Ukraine as the two primary US negotiators instead focus on Iran.
Although the administration should not have allowed this pivotal treaty to lapse completely, and with prospects dim about rekindling the spirit of negotiation needed for landmark, norms-based treaties, there is indeed a need to update and pursue a more robust deal. The nonproliferation architecture that emerged from the Cold War has not kept pace with the current proliferation reality. The emergence of China as a nuclear power fundamentally requires a reconsideration of nonproliferation and arms control agreements, with a shift from the bipolar to tripolar nuclear world. China is projected to possess 1,500 nuclear warheads by 2035 and is investing heavily in new missile silos, ballistic missile submarines, strategic bombers, and advanced delivery systems. Attempts to strike a trilateral agreement involving the United States, Russia and China have proven unfruitful, however this would be the most logical path forward and one that takes into account China’s rise as a nuclear power.
Beyond China’s rise, the rapid introduction of AI and its implementation in military settings has further complicated nuclear deterrence, as discussions surrounding the role of AI lag behind its adoption. Although some argue for AI’s integration into the nuclear chain of command, highlighting it could be used effectively in early detection, most recognize AI should not be empowered to make decisions regarding the use or deployment of nuclear weapons. To avoid this reality, Biden and Xi agreed to keep humans in control over their nuclear arsenals. Trump has not made a similar commitment, although AI’s role in the nuclear decision ladder could provide the basis for a shared consensus between the United States and China, allowing some limits on its usage. Discussions surrounding nuclear proliferation are no longer yesterday's debate and about yesterday’s technology, but require some future proofing. By having these conversations, this could lead to a new round of nonproliferation discussions, particularly given AI’s tendency to resort to nuclear escalation in war game scenarios.
Implications of “Friendly” Proliferation for European Deterrence
European countries, in turn, have not been complacent amidst these seismic shifts in nuclear deterrence. Whether out of fear or necessity, many have reevaluated partnerships as a result of global uncertainty surrounding nuclear proliferation and, in particular, the US commitment to European security. At the Île-Longue submarine base in March, French President Emmanuel Macron provided a substantive update to French nuclear doctrine and offered to extend France’s nuclear umbrella to select European partners through the concept of “forward deterrence”. This extends to ten partner countries, including Germany. His speech built on a landmark bilateral agreement between France and the United Kingdom–the Northwood Declaration–deepening nuclear cooperation and acknowledging any scenario that entails France using its nuclear weapons would also trigger a response from the United Kingdom. With uncertainty over the United States’ commitment to European security, it is clear that Europe may no longer be able to rely on the United States nuclear umbrella that has provided the bedrock of the continent’s security guarantees for decades.
Beyond casting doubts over its reliability and role in European security, parts of the Trump administration have championed a heretofore fringe policy known as “friendly” proliferation. Conversations around the utility and benefits of proliferation with like-minded partners have been at the core of nuclear weapons conversations since the 1960s, when China and France first developed their nuclear weapons programs. That conversation is being rekindled in Washington today, with parts of the Trump administration floating potential countries they might support in developing a nuclear weapons program. South Korea and Saudi Arabia are the two most likely candidates. A further list of US allies potentially reconsidering developing a nuclear weapons program includes: Germany, Poland, Sweden, Ukraine, Turkey, and Japan. Some of these countries are more likely to pursue the bomb than others. A record 80% of South Koreans are in favor of developing an indigenous nuclear weapons program. Other countries cited by proponents of “friendly” proliferation feel completely disconnected from the national sentiment or public opinion surrounding nuclear weapons. One example is Japan, the only country to have firsthand experience with the catastrophic damage associated with the use of nuclear weapons. Nearly 70% of Japanese citizens are opposed to their country developing a domestic nuclear weapons program. The recent decision by the United States to facilitate civil nuclear energy development with South Korea and Saudi Arabia highlights the seriousness of the administration's willingness to share US expertise on nuclear material with a friend. The administration’s decision to “substantially reduce” joint military exercises with South Korea further puts pressure on Korea to consider its own nuclear arsenal. This also comes at a time when the Pentagon is reportedly conducting an in-depth nuclear strategy review, including exploring ways to remove limitations on nuclear weapons, possibly to allow their use in regional wars.
Indeed, there is little conceivable benefit to this policy for the United States or for partners. Risks range from empowering individual countries to participate in nuclear brinksmanship, destabilizing delicate regional power dynamics, frozen or inert conflicts becoming kinetic again, and further entangling the United States and allies in overseas conflicts. This policy can at part be seen through the lens of the Trump administration’s transactional approach to allies and burden-sharing. Others point to Trump’s longheld fascination with nuclear weapons, dating back to the 1980s when he tried to convince Reagan to allow him to personally negotiate a nuclear disarmament agreement with Gorbachev. However, rather than rectifying perceived imbalances in burden-sharing, this “friendly” proliferation gambit isolates the United States, weakens its influence, and limits its ability to contribute to de-escalation.
For Germany, “friendly” proliferation adds to an already complicated picture when it comes to nuclear weapons. German citizens have a mixed perception on the role of nuclear weapons in their national defense. Germany benefits tacitly from nuclear weapons through NATO (a nuclear alliance), France and the UK’s nuclear deterrence, plus the US nuclear umbrella and pre-placement of nuclear weapons across the continent (including in Germany). Despite this backdrop, when asked about whether Germany should acquire the bomb, 72% of respondents are against developing a domestic deterrent as of 2025. However, in part due to the worsening security environment post-2022 invasion of Ukraine, today many Germans support a European nuclear deterrent with nearly two thirds in favor. In a surprising trend, however, younger generations in Germany are not as opposed to a domestic nuclear program as previous generations, further complicating Germany’s perceptions of nuclear weapon’s role in its deterrence posture.
In light of this complicated public perception regarding nuclear weapons, the Trump administration might see an opening and push Germany to reconsider the development of a domestic nuclear program, described as “nuclear signalling" . This would fall squarely in line with the administration’s attempts to shift the burden for alliance security, particularly to Germany, which the administration routinely singles out as a future leader in European security platforms. As recently as July 2026, the German government has reiterated its stance that it was not seeking a national nuclear weapons program. Any attempt by the US administration to push allies to develop a domestic nuclear weapons program, particularly Germany, is unlikely to be well received. However, conversations and pressure behind closed doors might lead to a worsening of relations. Although willingness to stand up to President Trump is fleeting, European leaders must avoid pressure to engage in proliferation talks. Instead, they must maintain the line of the international rules-based order to prevent a cascade of nuclear proliferation. Here, Germany can take a leadership role. The growing club of Middle Powers following Canadian Prime Minister Mark Carney’s famous Davos speech could present one format with which to push back against US insistence on nuclear proliferation.
Expanding access to civil nuclear capabilities risks more countries acquiring the bomb, which raises the likelihood of nuclear escalation. The Trump administration, in part due to President Trump’s predilection towards nuclear weapons and war, risks bringing the world closer to nuclear midnight, given its willingness to engage in “friendly” proliferation. His administration is launching what it refers to as an “American nuclear renaissance.” Europe–in particular Germany–has to stand by its principles and not become a party to wanton proliferation, even under the guise of burden shifting or enhancing regional security. Otherwise, the wars of the future will prove even more costly compared to today’s conflicts.