Between 27 April and 22 May 2026, 191 States parties to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) met in New York for its Eleventh Review Conference. Attended by international and regional observer organisations, as well as more than one hundred accredited civil society organisations, the conference ended, once again, without consensus on a final outcome document.
With this latest disappointment, the NPT review process has now gone sixteen years without producing an agreed document, raising important questions about the future of the treaty in its current review format, and about the broader nuclear order it helps sustain.
A mixed history of success
Often described as the cornerstone of the global nuclear order, the NPT rests on a triple bargain: states without nuclear weapons commit not to acquire them; nuclear-weapon States commit to pursue disarmament; and all States parties retain the right to access peaceful nuclear technology. Opened for signature in 1968 and entering into force in 1970, the treaty was initially conceived as a twenty-five-year arrangement intended to contain the spread of nuclear weapons while allowing time for the negotiation of more permanent solutions to nuclear dangers. When the treaty came up for extension in 1995, States parties decided to extend it indefinitely, creating a permanent structure accompanied by a five-year review cycle composed of three Preparatory Committee meetings and one Review Conference.
From the beginning, this arrangement has produced mixed results. On the one hand, the NPT has significantly slowed the spread of nuclear weapons. During the 1960s, former US President John F. Kennedy famously warned that by the 1970s there could be twenty-five nuclear-armed states. Today, there are nine. Besides the five states recognised by the NPT as nuclear-weapon States, only a small number have developed nuclear arsenals outside this framework. India, Pakistan and Israel never joined the treaty; North Korea withdrew from it; and South Africa dismantled its nuclear arsenal and joined the NPT as a non-nuclear-weapon State. The treaty also created the mandate for the development of an extensive safeguards and verification system under the International Atomic Energy Agency (IAEA), facilitating both monitoring and cooperation in peaceful nuclear technology. These safeguards systems helped identify diversion activities in cases such as Iraq and Libya in the 1990s and Iran in 2003, while continuing to provide confidence in the peaceful use of nuclear energy.
At the same time, the disarmament pillar—the central promise underlying this bargain—has remained far more difficult to fulfil. Although global arsenals have declined substantially from a Cold War peak of over 70,000 warheads, nuclear-weapon States continue to invest heavily in modernisation programmes and qualitative improvements to their arsenals. According to estimates by SIPRI and ICAN, more than USD 100 billion was spent on nuclear weapons in 2024, while recent monitoring reports indicate increased operational capabilities and renewed strategic competition among nuclear-weapon States. Recent years have also witnessed growing political and strategic pressures on disarmament efforts: the erosion of bilateral arms control agreements between the United States and Russia, the expansion of Chinese nuclear capabilities, modernisation programmes among NATO members, increasing opacity regarding nuclear postures in France, and the expansion of force structures in the United Kingdom. Meanwhile, many non-nuclear-weapon States have become increasingly frustrated with the perceived lack of progress under Article VI obligations. This frustration ultimately contributed to the negotiation of the Treaty on the Prohibition of Nuclear Weapons (TPNW) in 2017.
Procedural novelties, but the same political deadlocks at the 2026 Review Conference
Taken in isolation, a Review Conference without an outcome would not necessarily constitute a crisis. The NPT has survived periods of profound disagreement before.
After the indefinite extension in 1995, States parties adopted a package in 2000 containing the “13 Practical Steps” towards nuclear disarmament. The 2005 Review Conference failed to produce an outcome document, yet momentum was partially restored in 2010 with the adoption of a sixty-four-point Action Plan covering disarmament, non-proliferation and peaceful uses. This Action Plan provided a pathway towards achieving a world without nuclear weapons and remains an important agreed benchmark, despite limited implementation.
The 2015 Review Conference collapsed amid disagreements surrounding the establishment of a Middle East zone free of weapons of mass destruction. Middle Eastern states moved this issue into a separate UN process with the creation in 2019 of the United Nations Conference on the Establishment of a Middle East Zone Free of Nuclear Weapons and Other Weapons of Mass Destruction (WMDFZ Conference). Since then, this process has met repeatedly and created a relatively resilient negotiating framework that includes the twenty-two member states of the Arab League together with Iran and Israel, although the latter continues not to participate. The 2022 Review Conference similarly came close to consensus before disagreements on references to the situation at the Zaporizhzhia Nuclear Power Plant prevented adoption of a final document.
The challenge in 2026 was no longer a single failed conference. Rather, repeated failures are beginning to reshape the meaning and purpose of the review process itself. The conference began under difficult circumstances. Disagreements between the United States and Iran over committee leadership already signalled a tense atmosphere from the opening sessions. To protect the process, Conference President, Ambassador Do Hung Viet of Vietnam, attempted a different procedural approach. Rather than relying primarily on reports developed through the three Main Committees—dealing respectively with disarmament and security issues, safeguards and regional matters, and peaceful uses—he circulated an early “Zero Draft” during the second week of the conference.
This approach, resembling practices used in other multilateral settings such as the Biological Weapons Convention, was broadly welcomed by both states and civil society participants. Over the following weeks, the text underwent four revisions. Successive drafts became shorter and more politically focused, reducing explanatory language while adopting increasingly directive formulations. The principal debates remained familiar: nuclear disarmament commitments and the need to avoid a nuclear war, safeguards and compliance under IAEA safeguards, CTBT and strategic arms control language, ensuring the safe expansion of peaceful uses (including small reactors), regional security concerns (including the negotiations in the Middle East), and reform of the review process itself, with the suggested establishment of national reports and peer-review.
Despite this procedural innovation, longstanding political divisions prevailed. Disagreements over non‑compliance language — including contested references in the fourth draft — were a principal obstacle to an agreed outcome. Facing an almost inevitable veto, Ambassador Viet chose not to put the draft to a vote in part to avoid publicly singling out states.
That choice prevented an immediate collapse of the conference’s collegial space but did not produce a final document; as Ambassador Viet and UN officials noted, the failure leaves urgent questions about the future of the treaty. The nuclear order extends well beyond the NPT. Regional arrangements, safeguards institutions, nuclear‑weapon‑free zones and parallel diplomatic processes continue to operate even when NPT consensus proves elusive. The WMDFZ process will reconvene for its seventh session in November and remains important for regional confidence‑building. Just a few days later, attention will also shift to the first Review Conference of the TPNW. Other relevant meetings include the IAEA General Conference, the UN General Assembly First Committee, and the Conference on Disarmament in Geneva — forums where progress could compensate for the latest deadlock in the NPT.
The NPT Preparatory Committee will meet in Vienna in 2028, beginning a new review cycle that will conclude in 2031. The main challenge is breaking the pattern of repeated deadlock: the NPT’s resilience will depend on its ability to reform the process and to create genuine space for meaningful progress. Ambassador Viet’s procedural innovations were a step in that direction, but much more will be required if the treaty is to regain momentum and relevance, including progress on commitments already agreed.
