A half-century of US-Russian arms control ends with the expiration of the New START nuclear pact

The Kremlin said Thursday it regretted the expiration of the last remaining nuclear arms pact between Russia and the United States that left no caps on the two largest atomic arsenals for the first time in more than a half-century.

Arms control experts say the termination of the New START Treaty could set the stage for an unconstrained nuclear arms race.

Russian President Vladimir Putin last year declared his readiness to stick to the treaty’s limits for another year if Washington followed suit, but U.S. President Donald Trump has been noncommittal about extending it. He has indicated that he wants China to be a part of a new pact — something Beijing has rebuffed.

U.S. Secretary of State Marco Rubio said Wednesday that Trump has made clear “in order to have true arms control in the 21st century, it’s impossible to do something that doesn’t include China because of