A lone demonstrator promotes the powers of the 25th Amendment outside of the White House on 16 August 2017.

Constitution of the United States, Amendment XXV, Section 4, Paragraph 1:

Whenever the Vice President and a majority of either the principal officers of the executive departments or of 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 of the office as Acting President.