The last nuclear treaty between Russia and the United States expired on Thursday, February 5, abruptly ending decades of restrictions on how many warheads the two top powers can deploy and triggering fears of a global arms race.
New START, signed during a warmer period of relations, ended with President Donald Trump not following up on Russian counterpart Vladimir Putin’s proposal to extend the treaty’s limits for one year.
A NATO official speaking on condition of anonymity said on Thursday that “restraint and responsibility in the nuclear domain is crucial to global security.” The official said Russia and China were both ramping up their nuclear capabilities and that NATO “will continue to take steps necessary” to ensure its own defenses.
“Russia’s irresponsible nuclear rhetoric and coercive nuclear signaling demonstrate a posture of strategic intimidation,” the official said. Meanwhile, “China continues to rapidly expand and diversify its nuclear arsenal with more warheads and a larger number of sophisticated delivery systems,” they added.
The Kremlin on Thursday said it regretted the end of the last treaty governing the nuclear arsenals of Russia and the US and called it a negative step. Washington has said any new nuclear agreement would have to include China, but international efforts to encourage Beijing to join fresh talks have so far failed.
China’s foreign ministry joined a growing international chorus expressing regret on Thursday over the treaty’s expiry, but said Beijing “will not participate in nuclear disarmament negotiations at this stage.”
“China’s nuclear capabilities are of a totally different scale as those of the United States and Russia,” foreign ministry spokesman Lin Jian told a news conference.
Russia and the US together control more than 80% of the world’s nuclear warheads. China’s nuclear arsenal, meanwhile, is growing faster than any country’s, by about 100 new warheads a year since 2023, according to the Stockholm International Peace Research Institute (SIPRI).
China is estimated to have at least 600 nuclear warheads, SIPRI says – well below the 800 each at which Russia and the US were capped under New START. France and Britain, treaty-bound US allies, together have another 100.
‘Grave moment for international peace’
UN Secretary General Antonio Guterres called it a “grave moment for international peace and security” and urged Washington and Moscow to head quickly to the negotiating table.
“For the first time in more than half a century, we face a world without any binding limits on the strategic nuclear arsenals of the Russian Federation and the United States of America,” Guterres said in a statement.
“This dissolution of decades of achievement could not come at a worse time – the risk of a nuclear weapon being used is the highest in decades,” he said, after Russian suggestions of using tactical nuclear weapons early in the Ukraine war.
Pope Leo XIV said each side needed to do “everything possible” to avert 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,” the American-born pope said at his weekly general audience.
Russia’s Foreign Ministry said it considered that both countries are “no longer bound by any obligations or symmetrical declarations within the context of the treaty.” “The Russian Federation intends to act responsibly and prudently,” it added, but warned it was ready to take “decisive” countermeasures if its national security is threatened.
Trump to decide later
Trump has frequently lashed out at international limits on the US and called for nuclear testing to resume after a long moratorium, although he has not followed up. But some observers say the expiration of New START owes less to ideology than to the workings of the Trump administration, where career diplomats are sidelined, simply not having the bandwidth to negotiate a complex agreement.
Trump, asked in October in front of his helicopter about Putin’s proposal for a one-year extension, said it sounded “like a good idea,” but there were no subsequent negotiations. Secretary of State Marco Rubio said Wednesday that Trump would make a decision later and reiterated a call for a new agreement that includes China.
“The president’s been clear in the past that in order to have true arms control in the 21st century, it’s impossible to do something that doesn’t include China, because of their vast and rapidly growing stockpile,” Rubio said.
Joe Biden agreed with Russia to extend New START for five years after he defeated Trump in the 2020 election, but tensions between the two countries later soared over Moscow’s invasion of Ukraine.
The treaty, signed in 2010 in Prague by then presidents Barack Obama and Dmitry Medvedev, limited each side’s nuclear arsenal to 1,550 deployed strategic warheads, a reduction of nearly 30% from the previous limit set in 2002.
