The collapse of the New START treaty on 5 February removes the last legally binding limits on the world’s two largest nuclear arsenals at a time of heightened global tension and nuclear threats.

With inspections halted, data exchanges frozen, and no successor agreement in place, the end of New START marks a decisive breakdown of nuclear restraint between Russia and the United States, which together possess 87% of the world’s nuclear weapons.

The treaty’s verification, notification, on-site inspection and dispute resolution mechanisms provided ongoing communication, reduced uncertainty and helped prevent miscalculation. Their loss deepens mistrust and increases the risk of escalation.

The end of New START also exposes a central failure of deterrence and arms control. Arms control can regulate numbers and deployments but does not eliminate nuclear weapons. When restraint collapses or accidents or cyberattack happen, so does the system meant to prevent nuclear catastrophe.

Dr Tilman Ruff, ICAN founding chair, said:

“New START was the last treaty constraint on the most destructive weapons ever built. Its collapse leaves the world more dangerous and less predictable. 

“We are back in a full-scale arms race. Russia and the US could double their deployed nuclear weapons within months of New START’s end unless President Trump takes up President Putin’s offer to continue to respect New START’s limits. He should do this urgently.”

“But this would not be enough. Nuclear-armed states should start negotiations to verifiably eliminate their Doomsday arsenals, as they committed to do more than 50 years ago in the nuclear Non-Proliferation Treaty.”

“The Treaty on the Prohibition of Nuclear Weapons lights the path forward. It draws a clear line—nuclear weapons are illegal, unacceptable, and must be eliminated— and it provides the only internationally agreed, verified, time-bound framework to do so.”

The end of New START has immediate implications for Australia. Close to half the US B52 bombers planned for ongoing deployment at RAAF Tindal in the NT starting this year—which were modified to be unable to carry nuclear weapons under the New START Treaty—can quickly again be made nuclear-capable. That would mean that for the first time in decades nuclear weapons could be brought into and launched from Australia, even without Australia knowing.

Dr Ruff said:

“Australia cannot credibly support nuclear restraint and disarmament while standing outside the global ban, which has been joined by over half the world’s nations. The best way to put sovereign guardrails excluding nuclear weapons around our military cooperation with the United States is to join the ban treaty. The end of New START makes doing that, as Labor’s national policy platform commits, more urgent.”