A landmark arms control treaty between the US and Russia expired Friday after months in which neither side made serious efforts to preserve a Cold War-era agreement that did not cover an emerging China or evolving missile technology that did not exist a generation ago.
The Intermediate-range Nuclear Forces treaty came to an end with the US announcing that in the coming weeks it planned to test a new missile that would have been prohibited under the accord, which was signed in 1987.
Its demise comes amid rising doubts about whether the two countries will extend an agreement on long-range nuclear weapons scheduled to expire in 2021.
The Trump administration, which gave its six-month notice on February 2 of its pending withdrawal from the INF, had repeatedly said Russia was violating its provisions, an accusation President Barack Obama made as well.
"The United States will not remain party to a treaty that is deliberately violated by Russia," Secretary of State Mike Pompeo said in announcing the formal withdrawal, calling a Russian missile system prohibited under the agreement a "direct threat to the United States and our allies."
"This leads to the actual dismantling of the existing arms control system."
Chinese UN Ambassador Zhang Jun on Friday challenged what he said were efforts to make his country "an excuse" for the demise of the treaty: "You know, the United States is saying China should be a party in this disarmament agreement, but I think everybody knows that China is not at the same level with the United States and the Russian Federation."
David Wright, co-director of the Global Security Program at the Union of Concerned Scientists, said if Trump doesn't extend or replace New START it will be first time since 1972 that the US and Russia will be "operating without any mutual constraints on their nuclear forces."