President Donald Trump revealed Saturday the United States intends to withdraw from a 31-year-old nuclear weapons agreement with Russia, delivering a severe blow to the arms control regime that helped preserve peace since the Cold War.

With the INF Treaty on the scrap heap, there’s no legal or political framework for limiting the proliferation of nuclear weapons in the arsenals of world’s leading atomic powers.

Jon Wolfsthal, a nuclear expert on the National Security Council during the Obama administration, said a withdrawal would roil Europe.

“Things are just now calming down,” he said. “This would be another hand grenade in the middle of NATO to split the allies.”

“The US has started to brief allies with the possibility of withdrawal. But I don’t believe there has been any kind of interagency process in the administration,” said Jon Wolfsthal, a former senior director for non-proliferation and arms control at the NSC.

In a new report released on Tuesday, Global Zero’s Dr. Bruce Blair, a former Air Force launch control officer who’s a nuclear security expert at Princeton University, argues that the United States’ nuclear stance is a “vestige of the Cold War” that creates instability with an unnecessarily hefty price tag.