10. Nuclear disarmament, arms control, non-proliferation and security

The deterioration in the global nuclear order continued in 2025. Poor relations and lack of strategic dialogue among major nuclear-armed states continued to impede progress in disarmament and arms control. At the end of the year there was little indication that negotiations for any arms control framework involving China, Russia and the United States were imminent, in any format. This was despite a partial thaw in the relations between the two states with the biggest nuclear arsenals—Russia and the USA—and the approaching expiration of the bilateral 2010 Treaty on Measures for the Further Reduction and Limitation of Strategic Offensive Arms (New START).

Geopolitical tensions and regional conflicts highlighted the risk of nuclear weapon use as well as the possibility of uncontrolled release of radioactive materials resulting from attacks on civilian nuclear infrastructure. Although the seriousness of some of these risks and the importance of nuclear risk reduction were broadly acknowledged in multilateral forums, this did not translate into concrete action.

Attacks on nuclear installations in Iran

The global non-proliferation regime suffered a severe blow in June 2025 when Israel attacked Iran, with the USA later joining Israel’s attacks against Iranian nuclear facilities in a 12-day war. Although framed in terms of achieving the goal of non-proliferation, the attacks—condemned by several legal experts and states as a clear transgression of international law—under-mined that goal by precipitating an end to continuous monitoring of Iranian nuclear facilities by the International Atomic Energy Agency. The war demonstrated the vulnerability of non-nuclear weapon states to aggression by nuclear-armed states and served to normalize the ‘preventive’ use of force.

Multilateral processes

The 12-day war and the repeated attacks on Ukrainian nuclear power plants are likely to have an impact on the 2026 Review Con-ference of the 1968 Treaty on the Non-Proliferation of Nuclear Weapons (NPT). These negative trends come on top of concerns over the possible resumption of nuclear testing, the expiry of New START in February 2026 and other disagreements among NPT states parties—mostly linked to the lack of progress on nuclear disarmament—that are likely to place further strain on the discussions at the conference.

States parties of the 2017 Treaty on the Prohibition of Nuclear Weapons (TPNW) were unified in taking a strong position against nuclear deterrence and their continuing commitment to the previously agreed Vienna Action Plan. However, by the end of 2025, the prospects for building meaningful political momentum with nuclear-armed states for any new risk-reduction measures, let alone steps towards disarmament, remained highly unlikely.