The End of New START and the void in nuclear arms control

Translated by Annachiara Laino

On February 5, 2026, the New START Treaty, the last remaining agreement between the United States and Russia, expired. Its expiration means that, for the first time since the Cold War, the world's two major nuclear powers are no longer bound by any legally binding agreement on the number of warheads and delivery systems. This is a historic step that ushers in a period of great uncertainty for global security.

New START entered into force in 2011 and represented the most recent evolution in a long series of nuclear arms control treaties. It established precise limits: each country could deploy a maximum of 1,550 operational strategic nuclear warheads and no more than 700 delivery systems, including intercontinental ballistic missiles, submarine-launched missiles, and heavy bombers. Beyond the numbers, the treaty provided for a complex system of verification, mutual inspections, and data exchanges, considered essential to maintaining transparency and reducing the risk of miscalculations.

Even before its expiration, however, New START had become largely ineffective. Inspections had been suspended since 2020, initially due to the pandemic and then due to the worsening of relations between Washington and Moscow. In 2023, Russia announced the suspension of its participation in the treaty, while declaring its intention to continue to respect its limits unilaterally. The United States had made a similar declaration, but without a formal agreement and without active monitoring mechanisms: the treaty was now void.

Its expiration did not come suddenly, but it nonetheless marks a turning point. As several observers point out, the absence of legal limits does not automatically imply an immediate increase in arsenals, but it eliminates an important instrument of stability. Without transparency obligations, every move of the other becomes more difficult to interpret, increasing the risk of suspicion, preemptive reactions, and, in the long run, a new arms race.

International reactions were marked by concern. The UN Secretary-General described it as a "grave moment" for global peace and security, recalling that nuclear arms control has been a cornerstone of conflict prevention between great powers for decades. This view was shared by numerous experts, who warned that the end of New START effectively weakens the entire non-proliferation system.

The United States and Russia, for their part, blame each other for the failure. Washington maintains that any new agreement should also include China, whose nuclear arsenal is growing, while Moscow denounces the impossibility of negotiating in a context of intense political and military hostility. Beijing, however, rejects the idea of ​​a trilateral treaty, believing it disproportionate to compare its arsenal with those of the US and Russia.

From the current scenario, it therefore seems clear that, in the short term, it is unlikely that a new replacement treaty will be negotiated, given the numerous international tensions, including the war in Ukraine, on which negotiations between Russia, Ukraine, and the US itself are struggling to get off the ground.

At the same time, however, the current context is even more worrying, especially if this latest choice is interpreted as yet another move aimed at change and a step forward in an unprecedented historical phase, where, precisely, the end of the New START treaty is only the latest stage in the end of the multilateralism that characterized part of the twentieth century and the early 2000s, but was considered a fundamental step towards achieving peace and global balance.

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