The HALT Act of 2025 is a bill aimed at reducing nuclear weapons threats to the United States and the world. It establishes a policy direction for the U.S. government to lead international negotiations on nuclear arms control and disarmament, building on decades of bipartisan efforts to reduce nuclear arsenals. The bill calls for the U.S. to pursue agreements with other nuclear-armed countries on several key issues: freezing the testing, production, and deployment of nuclear weapons; reducing the number of deployed nuclear weapons; establishing policies against first use of nuclear weapons; preventing cyberattacks on nuclear command systems; and increasing transparency about nuclear arsenals. The bill also encourages the U.S. to seek Senate ratification of the Comprehensive Nuclear-Test-Ban Treaty and to negotiate a verifiable treaty preventing the production of weapons-grade uranium and plutonium. Most significantly, the bill prohibits the federal government from spending any money to conduct nuclear weapons tests that produce any yield, unless the President first reports to Congress about changes to the nuclear stockpile and Congress passes a joint resolution specifically approving the test. This effectively blocks nuclear weapons testing unless Congress explicitly authorizes it.