New START treaty expires, ending limits on US and Russian nuclear arsenals

The last U.S.-Russia nuclear arms treaty, New START, has expired, removing limits on the world's two largest atomic arsenals for the first time in over 50 years. This expiration raises concerns about a potential unconstrained nuclear arms race. Russia expressed regret, stating it will maintain a responsible approach to nuclear stability guided by national interests. The New START treaty, signed in 2010, capped warheads and delivery systems. Its expiration follows previous arms control pacts and a U.S. desire to include China in future agreements, which China has rejected.