In recent years, the United States and Russia have withdrawn from several major agreements developed over 40 years to control the spread of nuclear weapons, citing violations by the other side. Those treaties created a climate of strategic stability, minimizing the chances of nuclear war. Without them, a new arms race, reminiscent of the Cold War years, has begun, as both sides develop ultramodern, super-fast weapon systems capable of delivering a nuclear device anywhere on the globe within 15 minutes. U.S. and Russian military leaders also have embraced doctrines that maintain that a limited nuclear war using small, tactical nuclear weapons can be won. The last remaining treaty limiting U.S. and Russian nuclear arsenals will expire next February unless both countries agree to extend it. President Trump says he prefers to negotiate a broader pact that includes China, but Beijing has said it is not interested, and critics say a year is not enough time to negotiate such an ambitious accord. Meanwhile, a stalemate in talks over North Korea's denuclearization has added uncertainty to the future of arms control, as has the U.S. withdrawal from an international agreement halting Iran's development of nuclear weapons.