Following are excerpts from the 25th Amendment to th Constitution, which spells out the lines of presidential succession:
Section 1. In case of the removal of the president or of his death or resignation, the vice president shall become president.
Section 4. Whenever the vice president and a majority of the principal officers of the executive departments or such other body as Congress may by law provide, transmit to the President Pro Tempore of the Senate and the Speaker of the House of Representatives their written declaration that the president is unable to discharge the powers and duties of his office, the vice president shall immediately assume the powers and duties as acting president.