The Treaty on the Non‑Proliferation of Nuclear Weapons (NPT) is widely regarded as one of the greatest successes in the history of the United Nations.

In force since 1970, the accord was designed to curb the spread of nuclear weapons, advance nuclear disarmament and promote the peaceful use of nuclear energy.

It was adopted by 191 Member States, making it one of the most widely adhered‑to multilateral agreements ever and a cornerstone of international security.

In the last 54 years, nuclear weapons have never been used in a conflict, making the attacks on Hiroshima and Nagasaki in 1945 the only times that atomic bombs been dropped.

Dangerous, uncharted territory

But the global system governing nuclear weapons is facing its most serious crisis in decades. Most Cold War-era agreements have either been abandoned or expired: the 2010 US-Russia New START accord – which put a cap on the deployment of strategic nuclear warheads – expired in February without a successor in place.

At the time, UN Secretary-General António Guterres warned that the world was entering uncharted territory, with no remaining legally binding constraints on the nuclear arsenals of the United States and Russia – the two countries that together hold the vast majority of the world’s nuclear weapons.

This new era of mistrust was reflected in the Treaty’s last two review conferences, in 2015 and 2022, which ended without agreement on a substantive final document – underlining how divided States remain over priorities, obligations and the path forward.

This year’s review of the Treaty, which runs from 27 April to 22 May, will assess how well it is being implemented and whether it can deliver progress on disarmament, restraint and cooperation amid today’s security challenges.

Speaking at a press briefing on Friday, the UN’s High Representative for Disarmament Affairs, Izumi Nakamitsu, said that the event provides an opportunity for States to identify common areas, against the background of an extremely difficult security environment and increasingly concerning rhetoric.

“The threat of nuclear weapons use is becoming more frequent, and we don't want that to become normalised,” she said. “The more nuclear weapons states there are, the greater the risk of nuclear weapons being used by mistake.”

The review conference, the senior UN official added, “is not going to be just a box-ticking exercise. Diplomats need to lead it towards a successful outcome because it is about the future of the nuclear order in the world.”