Acting President of the United States

An acting president of the United States is a person who lawfully exercises the powers and duties of the president of the United States despite not holding the office in their own right. There is an established presidential line of succession in which officials of the United States federal government may be called upon to be acting president if the incumbent president becomes incapacitated, dies, resigns, or is removed from office (by impeachment by the House of Representatives and subsequent conviction by the Senate) during their four-year term of office; or if a president-elect has not been chosen before Inauguration Day or has failed to qualify by that date.

Presidential succession is referred to multiple times in the U.S. Constitution: Article II, Section 1, Clause 6, the Twentieth Amendment, and the Twenty-fifth Amendment. The vice president is the only officeholder explicitly named in the Constitution as a presidential successor. The Article II succession clause authorizes Congress to designate which federal officeholders would accede to the presidency if the vice president were unable to do so, a situation which has never occurred. The current Presidential Succession Act was adopted in 1947 and last revised in 2006. The order of succession is as follows: the vice president, the speaker of the House of Representatives, the president pro tempore of the Senate, and then the eligible heads of the federal executive departments who form the president's Cabinet in the order of creation of the department, beginning with the secretary of state.

The vice president immediately assumes the presidency in the event of the death, resignation, or removal of the president from office. Similarly, if a president-elect were to die during the transition period or decline to serve, the vice president-elect would become president on Inauguration Day. A vice president may also serve as acting president if the president becomes incapacitated. If both the presidency and vice presidency were to become vacant, the statutory successor would act as president but would not formally assume the office. To date, three vice presidents have briefly served as acting president without assuming the office of President of the United States.