For the first time in more than half a century, there are no binding restraints on the buildup of the largest nuclear forces on Earth. The New START treaty expired on Feb. 5, 2026, ending the last agreed limits on U.S. and Russian nuclear forces.
New START limited the number of strategic nuclear weapons the United States and Russia could deploy to 1,550 each. It also limited the missiles and bombers those warheads were loaded on, required on-site inspections and data exchanges, barred interference with satellite monitoring, and established a joint commission to discuss disputes. It did not limit the number of nuclear weapons each side could hold in reserve.
