Liviu Horovitz and Jonas Schneider

“The NPT Is Dead, Long Live the NPT!”

The Nuclear Non-Proliferation Treaty after the Failed Review Conference

SWP Comment 2026/C 33, August 2026

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DOI: 10.18449/2026C33

(English version of SWP‑Aktuell 38/2026)

The 2026 Review Conference of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) was held in New York in April-May. It was a failure because the delegations had been unable to agree on a final document. This was the third consecutive Review Conference to end without consensus – something that had never happened before in the 56-year history of the NPT. Ahead of the conference, some diplomats and experts had warned that another failure would be catastrophic not just for the treaty but for the entire nuclear order. That is the wrong conclusion to draw. The record of previous Review Conferences, what happened at this year’s meeting and the responses to its outcome all suggest that the NPT – the cornerstone of the nuclear order and an essential pillar of the broader international order – remains resilient. The growing nuclear inequality inherent in the NPT’s division of states parties into five nuclear-weapon states and 186 non-nuclear-weapon states polarises the multilateral nuclear debate in New York, Geneva and Vienna but does not threaten the treaty’s survival. The NPT would be at risk, however, if Russian and Chinese revisionism were to intensify further and US willingness to exercise leadership continued to wane.

“The NPT Is Dead, Long Live the NPT!”

The Nuclear Non-Proliferation Treaty after the Failed Review Conference

Liviu Horovitz and Jonas Schneider

The NPT is widely regarded as the institutional foundation of the global nuclear order. That is because the list of its 191 states parties encompasses almost every country and the non-proliferation norm codified in the treaty has been largely upheld since the NPT entered into force in 1970. Of the more than 20 states that have considered acquiring nuclear weapons during the past five-and-a-half decades, it is only India, Pakistan and North Korea that possess them today.

Since nuclear weapons confer immense military and strategic power, the NPT is also an important pillar of the global political order. Nuclear powers play a dominant role in many regions and alliances. The character and stability of the international order would be profoundly different if there were 20 or 30 nuclear-armed states rather than the nine that exist today.

Thus, the issue of just how stable the NPT is – and how much support it still commands – is not confined solely to nuclear policy; it is an indicator of the health and viability of the international order as a whole. Review Conferences are held at regular intervals to assess the state of the treaty. But many observers and diplomats continue to give too much weight to what happens at those conferences.

What the NPT is really about

Negotiated in the 1960s at the height of the Cold War, the NPT combines a strategic core rooted in power politics with a politico-diplomatic superstructure. At the strategic level, non-nuclear-weapon states undertake to forgo nuclear weapons in the expectation that their peers will do likewise so that none suffers a major security disadvantage. For their part, the five recognised nuclear-weapon states – the United States, Russia, the United Kingdom, France and China – pledge neither to transfer control over nuclear weapons to third countries nor to help them build the bomb themselves. An advantage for the nuclear powers is that the nuclear club remains exclusive. Furthermore, non-proliferation enables them to manage the risk of nuclear escalation more effectively and helps them maintain greater political influence over their non-nuclear allies. To verify compliance with the commitment to forgo nuclear weapons, all non-nuclear-weapon states parties accept safeguards on their peaceful nuclear activities that are administered by the International Atomic Energy Agency (IAEA). Those safeguards are intended to ensure that civilian nuclear facilities are not misused to produce nuclear weapons.

During the NPT negotiations, another two politico-diplomatic elements were added to this strategic core and incorporated into the treaty. First, states that forgo nuclear weapons are to enjoy the benefits of nuclear energy for peaceful purposes. Second, the nuclear-weapon states are to work towards nuclear disarmament through negotiations.

It is the NPT’s strategic dimension that matters most for the day-to-day security and defence policies of the state parties. But at the highly visible Review Conferences, the treaty’s politico-diplomatic superstructure moves into the spotlight. The debates that take place there are dominated by criticism of insufficient progress on nuclear disarmament as well as by regional security issues and conflicts (such as the current war against Iran) and demands for greater support for the peaceful uses of nuclear energy. Together with the great powers’ increasingly relentless pursuit of their own interests, these disputes routinely torpedo the consensus required to adopt a final document.

Even in more stable times, it had been difficult to ensure that these two dimensions of the NPT – the aspirations for progress voiced at diplomatic forums and the conservative logic of power politics that shapes state behaviour – were sufficiently reconciled to produce a document acceptable to all delegations. But with the international environment having further deteriorated since the previous Review Conference (in 2022), it was even less likely that agreement would be reached at this year’s meeting.

A conference burdened from the outset

Because of their direct implications for the NPT, both Russia’s war against Ukraine and the US-Israeli conflict against Iran weighed heavily on the Review Conference. Russia’s war of aggression against Ukraine violates the 1994 Budapest Memorandum, under which Moscow pledged to respect Ukraine’s independence, sovereignty and existing borders. In return, Ukraine voluntarily transferred the Soviet-era nuclear weapons deployed on its territory to Russia and joined the NPT as a non-nuclear-weapon state. Since the Kremlin has broken its commitments to Ukraine, some observers believe in retrospect that Kyiv’s earlier decision to relinquish nuclear weapons was naive.

From the outset of the full-scale invasion, Moscow has sought to use nuclear threats to deter European countries and the US from becoming more deeply involved on Ukraine’s behalf and to induce them to scale back their support. Thus, the Kremlin is using its nuclear arsenal to shield a conventional war of aggression, whereby that aggression is made possible in the first place. Many Western states regard such tactics as an abuse of nuclear deterrence. In their view, the arsenals of the NPT’s five nuclear-weapon states should serve only to maintain the territorial status quo, not to facilitate wars of conquest. Putin’s nuclear sabre-rattling continued even as the Review Conference was under way: while delegates were meeting, Russia conducted a flight test of its new Sarmat intercontinental ballistic missile and held a joint exercise with Belarus to rehearse using tactical nuclear weapons.

Even more than the war of aggression against Ukraine, it was the conflict with Iran that polarised the Review Conference. The US and several of its allies justified that conflict as a robust non-proliferation measure against what they described as Iran’s pursuit of nuclear weapons in violation of the NPT. For their part, Tehran and numerous other delegations condemned the US-Israeli attacks as an unlawful use of force by two nuclear-armed states against a non-nuclear-weapon state. Furthermore, critics regarded the attacks on declared Iranian nuclear facilities under IAEA safeguards – facilities at which the agency had found no indication of the diversion of nuclear material – as another affront to the NPT.

While the two wars put external pressure on the Review Conference, NPT diplomacy also came under strain from two troubling developments within the nuclear order itself. In February 2026, the New Strategic Arms Reduction Treaty (New START) – the last treaty to impose quantitative limits on US and Russian strategic nuclear forces – expired without a successor. This signalled the end of an era that dated back to 1972, when treaty-based ceilings first started to apply to the strategic forces of the two countries that have long possessed the world’s largest nuclear arsenals by far. Because China has been pursuing a rapid nuclear build-up for several years now, many observers fear that, following the expiration of New START, Washington and Moscow will similarly expand their arsenals in what will become a three-way nuclear arms race.

Beyond the activities of the three major nuclear powers, the UK announced in 2024 that it would invest more heavily in its nuclear weapons programme. One month before the NPT Review Conference, France’s president declared there would be a modest increase in the country’s nuclear arsenal and that its exact size would no longer be disclosed. Together, these steps threaten to bring an end to quantitative restraint on nuclear arsenals in several countries – and thus to a contextual factor long seen as helping stabilise the NPT.

The global norm against nuclear testing has recently come under pressure, too. In October 2025, US President Donald Trump announced that the US would resume nuclear weapons testing, citing alleged testing activities by China and Russia. In February 2026, the administration detailed its allegations against Beijing, pointing to seismic data. Whether the major powers will resume nuclear explosive testing remains uncertain. But most non-nuclear-weapon states regard the open-ended discussion on this subject in Washington, Beijing and Moscow as incompatible with the nuclear restraint embodied by the NPT.

Diplomatic efforts: Minimal consensus not reached but remains the goal

Under these difficult conditions, the opening weeks of the almost month-long conference brought to light the characteristic diplomatic strategies pursued by the various states parties. Many non-nuclear-weapon states sought to press the nuclear powers to take concrete steps towards disarmament, provide greater transparency about their arsenals and reaffirm earlier disarmament commitments in clearer terms. For their part, the NPT’s five nuclear-weapon states showed little willingness to restate old pledges or accept new constraints. Instead, they stressed the deteriorating security environment and sought to direct attention towards the misconduct of their competitors. The three Western nuclear-weapon states defended extended deterrence and nuclear sharing within NATO. Russia, meanwhile, sought to water down any references to nuclear testing and the humanitarian consequences of the use of nuclear weapons or to its war against Ukraine. And China sought to block demands for improved transparency. Thus, most delegations were intent mainly on defending their own narratives and imposing diplomatic costs on their opponents.

Conference President Do Hung Viet, Vietnam’s ambassador to the United Nations, tried at an unusually early stage to move beyond these diplomatic rituals, overcome the resulting deadlock and build agreement among the 130 delegations gathered in New York. Under the conference’s consensus rule, any one of the delegations could have blocked the adoption of an agreement. Just 10 days into the four-week conference, Do circulated a “zero draft” that was exceptionally concise and deliberately focused on general principles and overarching goals. The intention was to avoid more detailed wording, which would inevitably have provoked disputes, and to establish minimal common ground acceptable to all sides.

However, the limits of such an approach were revealed during the negotiations that followed. Instead of using the draft as a starting point for compromise, many delegations tried to get their priorities, caveats and red lines reinserted into the text. Each successive version of the draft reflected their competing demands without resolving the underlying substantive differences. Once again, the effort to adopt a modest declaration of shared goals had turned into a struggle over national narratives. States continued to press for language they knew other delegations would be highly unlikely to accept.

On the final day, the conference president made one last attempt to secure agreement by presenting a pared-down draft of a joint outcome document. To narrow the differences, Do had deleted or diluted contentious language, including on nuclear sharing, North Korea’s development of nuclear weapons, Russian attacks on nuclear facilities in Ukraine and stricter reporting requirements for the nuclear-weapon states. While the text still contained a range of political commitments – on dialogue, transparency, risk reduction, crisis communications and confidence-building – its disarmament ambitions and its handling of regional issues fell well short of the declarations issued at earlier Review Conferences.

Many non-nuclear-weapon states resented the concessions made to accommodate the power of individual delegations to block consensus, especially that of the nuclear powers. Meanwhile, hopes were raised that the delegations would adopt a final document on the basis of the lowest common denominator – a prospect that increased their willingness to compromise. One dispute, however, could not be resolved during the last-ditch efforts to reach agreement. Washington insisted on a passage addressing Iran’s nuclear programme, while Tehran resisted being singled out by name for condemnation. After further consultations, Do decided not to submit his draft for adoption; otherwise, either Washington or Tehran would have had to veto the text in public. Instead, Do withdrew the draft and announced that the conference had been unable to agree on an outcome. Thus, the proximate cause of the NPT Review Conference’s failure was the US-Iranian dispute. Whether other contentious issues would have led another state – perhaps Russia or China – to block consensus if the text had been submitted for adoption is impossible to say.

Clinging to the NPT – and to a dysfunctional process

The final push in the negotiations at this year’s Review Conference revealed something that went beyond the conference’s failure: an overwhelming majority wanted to achieve at least a minimal consensus document. Many non-nuclear-weapon states were prepared to accept a text that would have done little more than record the gradual erosion of the commitments, last agreed in 2010, on disarmament, non-proliferation and the peaceful uses of nuclear energy. Even that seemed preferable to yet another failed conference. Similarly, the nuclear-weapon states – particularly the three Western ones – continued to seek language they could support. And when the US–Iranian dispute ultimately made agreement impossible, delegations did not turn en masse against the NPT itself. Instead, they used their closing statements to emphasise the value and importance of the treaty. Thus, even under adverse conditions, states will continue to invest political capital in the NPT because its strategic core still serves their interests. Essentially, all governments want to limit the number of nuclear-armed states, even if they disagree on almost every other nuclear issue, as the conference demonstrated.

The NPT review process has never been insulated from major geopolitical conflicts, but now it is at risk of being overwhelmed by them. Disputes about disarmament and regional security made consensus difficult in the past. But during the Cold War, the US and the Soviet Union shared an enduring interest in preventing the further proliferation of nuclear weapons. At decisive moments, they managed to ensure their broader rivalry remained separate from this shared objective. After the Cold War, the unipolar stability of the global order underpinned by US military pre-eminence meant it was possible to negotiate more ambitious agreements (at the Review Conferences of 1995, 2000 and 2010), even though implementation fell well short of the goals established by those accords.

However, in the current era of great power competition, the willingness to keep unrelated conflicts out of the NPT framework has waned. Most troubling is the growing readiness of Moscow and Beijing to take nuclear risks, tolerate proliferation in some cases and use the review process to advance their foreign policy goals. Because NPT diplomacy depends on consensus, every conflict imported into the process becomes another potential veto point.

Under these more difficult conditions, the Review Conference format has become wholly dysfunctional. Since the establishment of a dedicated working group at the previous meeting (in 2022), states have debated introducing shorter statements, making committee mandates clearer, providing greater continuity between review cycles and conducting a structured discussion of national reports to improve transparency. Yet procedural reforms cannot solve the underlying problem. Most countries want each conference to produce a consensus document that reaffirms the treaty’s core bargain and its associated obligations. But few are willing to forgo either the review process as a forum for airing grievances or the veto power conferred by the consensus rule. Non-nuclear-weapon states use the meeting to demand nuclear-weapon states report on their disarmament efforts, even though it is unlikely that even modest arms-control progress will be made in the foreseeable future. Western states insist on calling out proliferation issues, despite the fact that a consensus-based forum cannot resolve them.

Thus, reforms fail for the same reason as the conferences themselves. Everyone wants more efficient procedures, but no one is willing to pay for them by narrowing their own agenda, surrendering leverage or setting aside favoured points of contention. For this reason, the format is likely to remain dysfunctional until the next Review Conference.

Military revisionism and America’s waning will to lead

Many problems come up for discussion at NPT conferences, but hardly any pose a genuinely existential threat to the treaty. While the resumption of nuclear testing, for example, would be a major setback for the nuclear order, it would be unlikely to cause the NPT’s collapse. The same applies to the absence of treaty-based ceilings on US and Russian nuclear arsenals, whether bilaterally or in an emerging tripolar nuclear relationship with China.

Iran’s nuclear advances and the US-Israeli attacks on the country pose greater risks to the NPT as both could create incentives for states to withdraw from the treaty. Furthermore, they could encourage individual states in the region to pursue their own nuclear weapon options. But even those developments would fundamentally endanger the NPT only if they triggered widespread proliferation, destroyed states’ confidence in the international system for controlling the spread of nuclear weapons or prompted the major powers to abandon all restraint in their nuclear non-proliferation policies.

Two broader trends, however, could well bring about the collapse of the NPT if they were to intensify further. The first existential threat stems from revisionist powers increasingly seeking to use their nuclear arsenals as a shield for expanding their regional spheres of influence by force. Russia and China possess both the will to challenge the territorial status quo and the capabilities to ensure that any US military intervention in their respective regions would be extremely costly. Their nuclear arsenals cast a long shadow over any conventional military conflict that Moscow or Beijing might launch.

As outlined above, the Kremlin has made effective use of nuclear threats in its war against Ukraine. China’s nuclear build-up serves a similar purpose. By increasing its ability to retaliate with nuclear weapons against US territory, including in extreme scenarios, Beijing is multiplying the risks to which the US would be exposed in a potential crisis over Taiwan. These revisionist strategies are significantly exacerbating insecurity across Europe and Asia, which, in turn, is driving demand for nuclear deterrence.

A second structural threat to the NPT is the erosion of Washington’s role in guaranteeing the security and legal order on which non-proliferation policy still depends. The US remains the international system’s most powerful actor, but its lead over its challengers has narrowed. During the “unipolar moment” of the 1990s and 2000s, there was little scope for China or Russia to openly challenge the US-led nuclear non-proliferation order. Today’s conditions give Beijing and Moscow stronger incentives to take greater nuclear risks and be less rigorous about the enforcement of the non-proliferation norm vis-à-vis their longstanding and now valued partners North Korea and Iran.

At the same time, domestic political trends are making Washington’s international engagement more selective, transactional and unpredictable. As the war against Iran has demonstrated, the US is quicker to resort to military force when it perceives its core interests under threat. Yet the Trump administration is also more willing to subordinate the non-proliferation agenda to short-term domestic priorities – such as keeping oil prices at politically acceptable levels – when the former conflicts with the latter. Whether adversaries or allies, countries with nuclear ambitions might therefore conclude that they can simply wait out US non-proliferation pressure. This change in Washington’s behaviour is important because, for half a century, US security guarantees and a predictable global framework reduced the incentives for other states to seek nuclear weapons of their own. Thus, the NPT is being weakened from within by doubts about US support and the binding force of the international legal order that America has thus far underwritten.

A lot of rhetoric but not much action from would-be proliferators

The more aggressively Russia and China act and the less reliably the US performs the role of protector of its allies and guarantor of the NPT, the greater the pressure on other states to take their security into their own hands (and, consequently, the greater the danger to the treaty). It is, above all, US allies that are debating whether to acquire nuclear weapons. These are countries that feel threatened by Russia and China and no longer consider Washington to be a reliable partner. They are also the states that do not complain loudest about the inequity of the NPT. As yet, no US ally is known to have decided to build the bomb. Nonetheless, some countries are testing the waters. They are challenging narratives, assessing capabilities, looking for partners and preparing for an even more fragmented order in which nuclear restraint would be harder to safeguard.

Several European NATO allies are entering into arrangements with France to boost nuclear deterrence – as a complement to, not a substitute for, NATO’s US-backed deterrence. While Paris and London are more closely coordinating their nuclear forces on a bilateral basis, France has launched a broader initiative whose initial participants were the UK, Germany, Belgium, Denmark, Greece, the Netherlands, Poland and Sweden; Norway joined in late May. The initiative does not entail shared control over nuclear weapons; rather, it encompasses nuclear consultations, joint military exercises for signalling purposes, visits to French nuclear sites and the integration of partners’ conventional capabilities. In addition, the rotation of French nuclear-capable aircraft to partner bases is envisaged. At the same time, some US allies on NATO’s eastern flank are seeking integration into the Alliance’s nuclear-sharing arrangements through certification of their aircraft, crews and bases for the nuclear mission, but without US nuclear weapons being hosted on their territory.

In several NATO countries, however, the issue of the potential need for national or shared control over nuclear weapons is once again being addressed. In Poland, Finland, Sweden and Germany, politicians across the political spectrum – both in government and in opposition – are pondering whether their countries might require nuclear options independent of the US and France in the medium term. The possibility of Ukraine acquiring nuclear weapons has been raised, too.

The fact that these debates are taking place does not mean any decisions to acquire nuclear weapons have been made. What they reflect is growing insecurity in Europe: politicians are searching for a way out of their strategic predicament, calling for clearer security commitments from Washington or testing domestically which alternatives to dependence on US protection might be politically viable. So far, there is no evidence that the states concerned are making weapons-related technical preparations that would give them a head start if they decided to pursue nuclear weapons of their own. Such a far-reaching step would entail enormous political costs and, as yet, does not seem necessary to any of these countries. The Trump administration appears to be responding to Europe’s debates. It is pressing Europe to strengthen its conventional forces while emphasising the durability of the US nuclear guarantee to NATO.

In Asia, South Korea and Japan continue to rely on US extended nuclear deterrence. But in both countries, nuclear consultations with Washington, efforts to expand dual-use technological expertise and public debates about acquiring nuclear weapons have intensified. The US now allows Seoul to enrich uranium and reprocess spent fuel (which can yield plutonium) for civilian purposes. It is also allowing Seoul to build nuclear-powered submarines and helping source the necessary uranium fuel. None of this involves the design of a nuclear warhead, but it does create new nuclear expertise and capacities that, if needed, would reduce the time required for South Korea to produce its own nuclear weapons. Japan has long possessed facilities for uranium enrichment and spent-fuel reprocessing. There is no indication, however, that Tokyo is planning to acquire nuclear weapons. At present, it is only upgrading its conventional forces.

In the Middle East, the non-proliferation norm is not currently at risk among the region’s US partners, although it has never been internalised there. Saudi Arabia’s proliferation calculus reflects Iran’s trajectory and uncertainty over Trump’s regional policy and US security guarantees. Riyadh has launched a civilian nuclear programme, kept open its uranium-enrichment option and signed a 2025 mutual defence pact with Pakistan that envisages joint deterrence. Whether this means Saudi Arabia is under Pakistan’s nuclear umbrella remains unclear. Turkey, meanwhile, is having civilian reactors built but is pursuing neither uranium enrichment nor reprocessing. Ankara therefore appears to be holding back on nuclear options while rearming only conventionally.

Germany’s stake in a robust nuclear order

Predictions of further nuclear proliferation have repeatedly proved overly pessimistic. The number of nuclear-armed states has remained low, and the NPT has survived crises that at one time appeared to pose an existential threat. Yet resilience offers no guarantee of the treaty’s survival.

Whether the NPT survives will not be decided at its Review Conferences. More important is the strategic environment in which states assess their security options. For the treaty to remain an effective barrier to proliferation, the US and/or its allies must 1) curb revisionist ambitions; 2) provide credible security guarantees; 3) uphold the international prohibition on the use of force, which makes nuclear restraint attractive; and 4) support bodies, such as the IAEA and the Nuclear Suppliers Group (NSG), that make it difficult to implement proliferation decisions.

These general criteria provide a basis for assessing Germany’s contribution to strengthening the NPT. The German government’s substantial investments both in its own security and in that of individual European frontline states – such as Lithuania and Ukraine – are valuable from a non-proliferation perspective. They are intended to help prevent Russian expansion and alleviate the fear of abandonment among partners on Europe’s eastern flank – a perception that has historically spurred proliferation. But these measures do not amount to a security guarantee; and for that reason, Berlin’s parallel efforts to keep the US committed to NATO through greater burden-sharing and to involve Washington in a possible postwar settlement for Ukraine are all the more important. Meanwhile, Germany relies on others to contain Chinese revisionism in Asia, while its support for the IAEA and NSG remains exemplary.

However, Washington’s approach to the prohibition on the use of force is increasingly forcing Berlin to perform a balancing act – not least because of the NPT. Targeted strikes against military nuclear programmes may be justified as a last resort and may even strengthen the treaty. Wars of choice aimed at reshaping the geopolitical order, on the other hand, normalise the use of force. If no one expects the rules to apply to great powers any longer, other countries will not help Germany hold Russia or China accountable for violations. In a world of wars of aggression, more states would likely seek nuclear weapons, which would have consequences for the NPT.

But calling out violations of the existing order when the US is responsible has never been as difficult for Berlin as it is today. Trump takes criticism personally, and he could cause irreversible damage to NATO at a time when the Alliance remains indispensable to Germany. Berlin’s political calculus must therefore consider how quickly and how directly German security would be undermined by violations of global rules.

Dr Liviu Horovitz is an Associate in SWP’s International Security Research Division. Dr Jonas Schneider is Deputy Head of the division. This SWP Comment was produced as part of the Strategic Threat Analysis and Nuclear (Dis-)Order (STAND) project. The authors would like to thank Emma Bossert for her excellent research assistance.