War Powers

The Constitution divides war powers. Article I gives Congress the power to declare war, raise and support armies, maintain a navy, and fund the military, with army appropriations limited to two years. Article II makes the President commander in chief. The framers changed an early draft from Congress's power to make war to declare war, which James Madison explained as leaving the President power to repel sudden attacks. Congress has formally declared war eleven times in five conflicts, the last in June 1942.

Since World War II, presidents have committed forces to major conflicts, including Korea and Vietnam, without declarations, relying on their command authority, United Nations resolutions, or congressional authorizations for the use of military force. After Vietnam, Congress passed the War Powers Resolution of 1973 over Richard Nixon's veto. It requires the President to report to Congress within 48 hours of introducing forces into hostilities and to withdraw them within 60 days, plus 30 for withdrawal, unless Congress authorizes the action. Every President since has questioned its constitutionality, and enforcement has proved weak.

Most modern operations rest on authorizations rather than declarations. The 2001 authorization to use force against those responsible for the September 11 attacks has been cited for operations against groups in many countries for more than two decades, and the 2002 Iraq authorization was long criticized as outdated until Congress repealed it, along with the 1991 authorization, in December 2025. Presidents of both parties have ordered strikes without specific authorization, citing self-defense and national interest, including the 2011 air campaign in Libya and, in 2025, strikes on Iranian nuclear facilities and on vessels the administration said were carrying drugs from Venezuela, and in January 2026 a military operation in Venezuela that captured its leader, Nicolas Maduro. Each renewed debate in Congress over reasserting its constitutional role.