The Twenty-fifth Amendment to the United States Constitution deals with presidential succession and disability. It also provides for the transfer of the president's powers and duties to the vice president, either on the initiative of the president alone or on the initiative of the vice president together with a majority of the president's cabinet. In either case, the vice president becomes acting president until the presidential powers and duties are returned to the president.

Section 4 addresses the case of a president who is unable to discharge the powers and duties of the presidency but cannot, or does not, execute the voluntary declaration contemplated by Section 3.[3]: 117  It allows the vice president, together with a "majority of either the principal officers of the executive departments or of such other body as Congress may by law provide",[note 3] to issue a written declaration that the president is unable to discharge his duties. Immediately upon such a declaration being sent to Congress, the vice president becomes acting president[note 4] while (as with Section 3) the president remains in office, albeit temporarily divested of authority.[9]