Before Russian President Vladimir Putin declared on Tuesday that Moscow was suspending its participation, the last pact that restricts Russian and American nuclear weapons was already in dire danger.

It may now be beyond repair, increasing the possibility of a new weapons race that would occur concurrently with the conflict in Ukraine and in which neither side could rely on the reliable framework that successive nuclear agreements had supplied for more than 50 years.

Security analysts said that could hugely complicate the delicate calculus that underpins mutual deterrence between the two countries, while also spurring other powers such as China, India and Pakistan to build up their nuclear arsenals.

In a major speech almost a year after his invasion of Ukraine, Putin said Russia was not abandoning the New START treaty – the agreement signed in 2010 that limits the number of Russian and U.S. deployed strategic nuclear warheads.

But nuclear experts noted the treaty contains no provision for either side to “suspend” its participation, as he said Moscow was doing – they only have the option to withdraw.

Putin said Russia would only resume discussion once French and British nuclear weapons were also taken into account – a condition the analysts said was a non-starter, as it was opposed by Washington and would require a complete rewriting of the treaty.

William Alberque, director of strategy, technology and arms control at the International Institute for Strategic Studies, said Russia had decided it could live without New START but was seeking to put the blame on Washington.

“They’ve already made the calculation the treaty will die. The effort will be to pin the actual loss on the United States,” he said in an telephone interview.

According to Alberque, the treaty effectively caps the number of warheads that each side can launch on a single missile. If it were to be abandoned, this would result in an immediate increase in the number of warheads.

The Federation of American Scientists estimates that Russia possesses 5,977 nuclear warheads overall, compared to the United States’ 5,428.

“That could happen fast,” Alberque added, “both sides could jump from 1,550 deployed strategic weapons to 4,000 right away.”

According to him, this could be unstable since it poses a “use or lose” choice where concentrated numbers of the enemy’s warheads present more alluring targets.