US-Russia Nuclear Treaty Expires, Sparking Arms Race Fears

The last remaining nuclear arms control treaty between the United States and Russia expired at midnight GMT on Thursday, raising the threat of a renewed global arms race. The New START pact, which for decades limited the world's two largest nuclear arsenals, has officially lapsed without an extension.

With the treaty's expiration, both the US and Russia are no longer bound by its upper limits on strategic nuclear weapons. This development marks a significant shift in global security dynamics, ending a long-standing framework for nuclear stability.

Russia's Foreign Ministry stated that the country would act responsibly but warned it would take "decisive" measures if its security were threatened. Meanwhile, Washington has not announced any plans to voluntarily adhere to the treaty's former limits beyond the deadline.

Figure 1: The expiration of the New START treaty removes caps on strategic nuclear arsenals for the world's two largest nuclear powers.

Why Negotiations Stalled: The China Factor

The New Strategic Arms Reduction Treaty (START), signed in 2010, capped both the US and Russia at 1,550 deployed strategic nuclear warheads. Despite efforts to keep it alive, negotiations for an extension ultimately failed.

Russian President Vladimir Putin had previously proposed a one-year extension, a suggestion that US President Donald Trump initially called "a good idea" in October. However, no subsequent negotiations took place to formalize an agreement.

The primary sticking point became President Trump's insistence that any future arms control deal must include China. This demand was consistently rejected by Beijing and considered unnecessary by Moscow. In a video call with Chinese President Xi Jinping, Putin reiterated Moscow's commitment to "act in a balanced and responsible manner" while remaining open to negotiations.

Figure 2: Negotiations between US President Donald Trump and Russian President Vladimir Putin stalled, largely over the demand to include China in a future arms control agreement.

US Secretary of State Marco Rubio affirmed this position on Wednesday, stating that Trump would decide on the treaty later but adding that "it's impossible to do something that doesn't include China, because of their vast and rapidly growing stockpile."

This view was echoed by German Foreign Minister Johann Wadephul, who called on China to show "restraint" in its weapons development and argued that future arms control efforts must include Beijing.

Global Leaders Warn of Rising Nuclear Threat

International leaders have expressed grave concern over the treaty's expiration. UN Secretary-General Antonio Guterres described it as a "grave moment for international peace and security." He warned that "the risk of a nuclear weapon being used is the highest in decades" and implored both nations to return to negotiations without delay.

Pope Leo XIV also weighed in during his weekly general audience, calling for de-escalation from a new arms race. "I urge you not to abandon this instrument without seeking to ensure that it is followed up in a concrete and effective manner," he stated.