By Jennifer Hansler, Kylie Atwood, CNN
(CNN) — The expiration of the last remaining nuclear treaty between the United States and Russia on Thursday has sparked fears about a nuclear arms race, with the two biggest nuclear superpowers without limits on their arsenals for the first time in decades.
“The worst case is it spirals and then some unforeseen or foreseeable incident touches off a conflict that escalates rapidly to a nuclear conflict,” said Thomas Countryman, a former acting undersecretary of state for arms control and international security.
Though some experts argue the limitations of the New START treaty were outdated and unnecessarily constrained the US, especially when China is looking to expand its nuclear arsenal.
The landmark treaty went into force in February 2011. It capped both countries at 1,550 deployed nuclear warheads; 700 deployed intercontinental ballistic missiles, submarine-launched ballistic missiles and heavy bombers equipped to transport nuclear weapons; and 800 “deployed and non-deployed” launchers. It put limits on Russian intercontinental nuclear weapons that could reach the US.
But critics of the treaty, including President Donald Trump, pointed out it did not cover China, which is rapidly expanding its nuclear arsenal and could have some 1,500 nuclear warheads by 2035 if they continue to expand their stockpile at the current pace, according to a Pentagon report from 2022.
The treaty was originally in place for 10 years. In 2021, the US and Russia agreed to extend it for another five years, through February 4, 2026.
The agreement was not eligible to be extended again, but the two countries could agree to continue to adhere to the caps outlined in the treaty. Concerns over the future of arms control – which the US and Russia have worked on together for decades – comes as Trump also vowed last year that the US would resume nuclear testing, but there has been no movement towards that end.
Last September, Russian President Vladimir Putin proposed doing so for another year. At the time, Trump said the proposal “sounds like a good idea to me.”
However, Trump in recent weeks has expressed little concern about the lapse, telling the New York Times, “If it expires, it expires. We’ll do a better agreement.”
And on Wednesday, Secretary of State Marco Rubio suggested that the US would not agree to maintain the limits of the treaty, citing Trump’s call for a nuclear deal between the US, Russia and China.
“The president has 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,” he said.
Beijing has consistently rebuffed the idea of trilateral negotiations both privately and publicly.
‘Erroneous and regrettable’
Russia’s Foreign Ministry on Wednesday said they had received no answer from the Trump administration and that public comments from the US government indicate “that our ideas have been deliberately left unanswered.”
“This approach seems erroneous and regrettable,” the statement said.
The foreign ministry said that “in the current circumstances,” they assume the two countries “are no longer bound by any obligations or symmetrical declarations in the context of the Treaty, including its core provisions, and are in principle free to choose their next steps.”
Asked about the statement, a Trump administration official told CNN, “President Trump has spoken repeatedly of addressing the threat nuclear weapons pose to the world and indicated that he would like to keep limits on nuclear weap