Article II, Section 2 of the Constitution designates the president as commander in chief of the Army and Navy. This gives the president broad authority to direct military operations, order deployments, and respond to attacks without waiting for Congress. Congress holds the power to formally declare war under Article I, Section 8, but has not issued a formal declaration since World War II. Instead, it has relied on Authorizations for Use of Military Force and the War Powers Resolution to constrain presidential discretion, with uneven success.