The eleventh Review Conference of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), currently underway at United Nations headquarters in New York City, is happening amidst a geopolitical context that is in many ways more unstable than at any point since the end of the Cold War. The war in Ukraine, the confrontation between Israel, the United States, and Iran, tensions in the South China Sea and around Taiwan, as well as the dismantling of bilateral nuclear arms control mechanisms, are collectively undermining the global security architecture.

Against this backdrop, the growing influence of the Treaty on the Prohibition of Nuclear Weapons (TPNW) reflects not merely activist pressure at the margins of the international system, but a deepening crisis of confidence in the existing disarmament architecture. Indeed, for many non-nuclear-weapon states, the TPNW represents an effort to reinforce, rather than replace, the disarmament commitments embedded in Article VI of the NPT. Their concerns about the state of the multilateral non-proliferation and disarmament regime, as well as their sincere commitment to nuclear disarmament – as embodied in the TPNW – should be taken seriously and not dismissed.

At a moment of heightened nuclear risk and accelerating arms competition, the credibility of the non-proliferation regime increasingly depends not on treating the NPT and TPNW as competing frameworks, but on finding ways for them to function in a mutually reinforcing manner.

The disarmament crisis and the TPNW

Nuclear disarmament, long treated as a key, yet distant objective of the NPT, now lies at the very heart of contestation by many non-nuclear-weapon states, which contend that the nuclear-weapon states have failed to honour their political commitments to pursue disarmament in good faith under the Treaty.

This comes at a time when the multilateral architecture that sustains the NPT is steadily unravelling and the Treaty itself risks becoming dysfunctional. Two successive Review Conferences, in 2015 and 2022, failed to adopt a substantive final document. This year’s Conference has convened against a backdrop of the erosion of existing agreements across each of the NPT’s three pillars: disarmament, non-proliferation, and peaceful uses of nuclear technology. NPT States Parties also need to navigate the broader “deterioration of bilateral arms control” that has reduced the NPT’s capacity to rely upon mechanisms, such as risk reduction, to stabilise relations between the principal holders of nuclear arsenals. The result is a non-proliferation regime that remains juridically intact but politically enfeebled, struggling to respond to the manifold global and regional crises.

The adoption of the TPNW in 2017 – and its entry into force in 2021 – reflects the exhaustion of a significant proportion of states and civil society actors in the face of the deficit in implementing the NPT’s disarmament provisions. For TPNW States Parties, the treaty introduces a clear prohibition norm modelled on the conventions applicable to chemical and biological weapons, comprehensively banning the use, threat of use, development, possession, and transfer of nuclear weapons.

Since its adoption, supporters have emphasised that the TPNW should be read as an instrument for implementing Article VI of the NPT rather than as its competitor. For states party to both instruments, the NPT establishes the general framework, whilst the TPNW specifies the content of the prohibition norm and extends the normative framework, for instance through the formulation of positive obligations of reparation and assistance to victims of nuclear weapons use and testing.

Tensions around the TPNW do not arise from a formal incompatibility but from a conflict of representations. For nuclear-weapon states and their allies, the TPNW is perceived as undermining the stabilising function they attribute to deterrence. Critics still argue that both treaties are incompatible, that the TPNW undermines the NPT, creates frictions within NPT membership, and that the TPNW does not constitute a viable path to disarmament.

Nevertheless, for a growing majority of non-nuclear-weapon states, the TPNW constitutes the only credible signal that nuclear disarmament – but also humanitarian and climatic risks associated with nuclear weapons – are being taken seriously.

Lever for possible reconfiguration

Three concrete recommendations might be advanced at the eleventh Review Conference in order to transform the NPT-TPNW relationship from a source of fragmentation into a lever for stabilisation. This would help reinvigorate disarmament efforts under the NPT and counter the perception held by many non-nuclear-weapon states that the Treaty regime is dysfunctional and incapable of making a meaningful contribution to disarmament.

First, the final document should incorporate a nuanced recognition of the TPNW’s contribution to the implementation of Article VI, indicating that, for its States Parties, the TPNW complements the NPT by reinforcing the prohibition norm and would not create new obligations for non-parties, but would reduce political polarisation. It would also send a signal to mass publics – increasingly alert to climatic and humanitarian concerns – that the non-proliferation regime is not locked in a status quo.

Second, a structured dialogue mechanism should be established between the NPT Review Conferences and the Meetings of States Parties to the TPNW. Supported by the UN and the International Atomic Energy Agency (IAEA), such a mechanism could focus on cross-cutting themes including verification, humanitarian consequences, climatic risks, and the effects of emerging technologies on deterrence stability. It would provide a forum for the exchange of expertise and the formulation of joint recommendations on risk reduction, beyond doctrinal divergences regarding the legitimacy of deterrence.

Third, European states should be encouraged to initiate a process of ‘practical convergences’ with the spirit of the TPNW, without requiring immediate accession. This could take the form of political declarations restricting the role of nuclear weapons to the prevention of existential threats, excluding preventive use, and reaffirming the centrality of human decision-making in any launch procedure. Such an approach would be consistent with the particular responsibility the international community continues to assign to the NPT, whilst acknowledging that the risks induced by emerging technologies necessitate a redefinition of red lines, including for nuclear-armed states.

Ultimately, the central question of the 2026 Review Conference is not whether the NPT or the TPNW will ‘prevail’, but whether states will consent to make them work in concert early enough to prevent a future crisis from rendering their theoretical divergences moot. The outcome of this conference will determine whether the international community endorses a situation of systemic nuclear insecurity, or whether it chooses to harness the normative energy of the TPNW to revitalise an NPT whose legitimacy is waning.

The European Leadership Network itself as an institution holds no formal policy positions. The opinions articulated above represent the views of the authors rather than the European Leadership Network or its members. The ELN aims to encourage debates that will help develop Europe’s capacity to address the pressing foreign, defence, and security policy challenges of our time, to further its charitable purposes.

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