This bill, titled the "Restricting First Use of Nuclear Weapons Act of 2025," aims to significantly limit the President's unilateral authority to initiate a nuclear attack. It establishes a policy that no first-use nuclear strike should be conducted without a prior declaration of war by Congress, asserting that such a monumental decision, which constitutes a major act of war, falls under Congress's constitutional power to declare war. The legislation explicitly prohibits the obligation or expenditure of federal funds for any first-use nuclear strike unless it is conducted pursuant to a war declared by Congress that expressly authorizes such an action. A "first-use nuclear strike" is defined as an attack using nuclear weapons against an enemy that is not in response to a confirmed nuclear strike against the United States, its territories, or its allies, as verified by the Secretary of Defense and the Chairman of the Joint Chiefs of Staff.