Can the NPT review conference stop a new nuclear arms race?

Amid the expiration of New START and fears of secret weapon testing, the world’s oldest arms reduction treaty is under strain, writes Iona Allan.

The World Today

Published 16 March 2026 — 3 minute READ

Image — Emmanuel Macron, the French president, speaking at the Île Longue nuclear submarine base, outlines how France’s nuclear deterrent may help strengthen security in Europe. Photo: Yoan Valat/ POOL / AFP via Getty Images.

Iona Allan

Assistant Editor, The World Today

On 27 April, some 191 countries will gather for several weeks of discussions at the United Nations in New York to review commitments towards the Nuclear Non-Proliferation Treaty (NPT), amid rising concerns over the future of global arms control – and whether nuclear weapons may soon be deployed in space. 

The treaty, which came into force in 1970, is regarded as the cornerstone of nuclear non-proliferation and remains the only binding framework obligating nuclear-armed signatory states to pursue disarmament. These commitments are assessed every five years at the review conference at UN headquarters. Friction between Russia and the West over the Zaporizhzhia nuclear power plant in Ukraine derailed negotiations at the previous conference, which was delayed until 2022 and ended without the adoption of a consensus document. The meeting in 2015 also failed to reach an agreement. 

Trump’s threat to resume US tests could unleash a spiral of global testing.

Shashank Joshi, defence editor of ‘The Economist’

Experts warn that the headwinds facing delegates at this year’s gathering are even greater. ‘The mood at the conference will be profoundly affected by the demise of New START – the arms reduction treaty between the United States and Russia,’ said Shashank Joshi, defence editor of The Economist. Its expiration on 5 February has left the two most heavily armed nuclear states without limits on their stockpiles for the first time in decades. 

‘There are also huge questions around the future of the Comprehensive Nuclear-Test-Ban Treaty, after US allegations that China has [secretly] conducted a yield-producing nuclear test, and Donald Trump’s threat to resume US tests which could unleash a spiral of global testing. All of that will frustrate progress towards anything resembling disarmament at the conference,’ said Joshi. 

Other aspects of Trump’s nuclear policy have unsettled allies over the past year. In June 2025, the US conducted strikes on Iranian nuclear facilities, while in October, for the first time in 20 years, the US national security strategy omitted any mention of North Korean denuclearization. The administration’s delay in appointing a Secretary of State for Arms Control until October has also prompted concerns about the level of US engagement at the month-long conference. 

European deterrence 

Experts say that, for America’s allies, negotiations at the NPT conference are likely to be tied to wider discussions about collective defence and burden sharing. The US and Russia account for 90 per cent of global nuclear stockpiles; while France and Britain – Europe’s two nuclear-armed states – have a fraction of that with just over 500 warheads combined.

For decades the US has provided ‘extended deterrence’ to non-nuclear armed states in Europe, seeing this as a way of reassuring allies that they don’t need nuclear weapons, said Marion Messmer, director of Chatham House’s International Security Programme.

 ‘The US has never been supportive of other states acquiring nuclear weapons, and they still aren’t,’ she said. ‘But Trump’s comments over the past few years around whether he would support allies in a crisis have put the reliability of NATO’s collective defence clause – Article V – in doubt.’ Washington has said its nuclear deterrence arrangements in Europe still hold, but according to Messmer, ‘Trump’s chipping away at conventional security guarantees is undermining this.’ As fractures in the transatlantic alliance deepen, European leaders are reportedly seeking alternative deterrent arrangements.

‘There’s much more interest in Europe now around the question of how to extend the French and British nuclear deterrents in a more tangible way,’ said Joshi, who thinks this will raise ‘some difficult questions’ at the review conference. In Munich last month, Friedrich Merz, the German chancellor, and French President Emmanuel Macron were said to be in talks about how to extend France’s European nuclear deterrent. Unlike Britain, France’s weapons are not part of NATO’s sharing arrangements. In a speech at Île Longue submarine base in March, Macron announced an ‘advanced deterrence strategy’ that would involve closer cooperation with its European allies and an increase in the size of France’s nuclear arsenal.  

Space risks

Analysts are also concerned that nuclear weaponry could soon be deployed on a new frontier: space. ‘Whether Russia is developing nuclear weapons to be placed in space is a growing concern for many countries,’ said Messmer, pointing to the anti-satellite missile test Moscow conduced in 2021, which sparked fears about collisions and galvanized calls for international norms in space. 

Whether Russia is developing nuclear weapons to be placed in space is a growing concern for many countries.

Marion Messmer, director, International Security Programme, Chatham House

‘The challenge at the conference,’ she added, ‘is that consensus has to include Russia, and Russia is unlikely to want to discuss any space programmes that its currently developing.’ Moscow’s intentions in space are also likely to be alarming its most important ally, said Joshi. ‘China will be concerned about this given the disproportionate impact that low-earth orbit [activities] could have on its own satellite constellations.’ It’s also likely ‘that other middle and smaller powers with big space ambitions will be very worried by this,’ he added.

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