Section 4 addresses an inability the president does not declare. The vice president and a majority of the principal officers of the executive departments, or another body Congress creates by law, transmit a written declaration. The vice president then acts as president. If the president disputes the declaration, the amendment creates a further written process and requires two-thirds of both chambers to keep the vice president as acting president. This is a demanding continuity procedure, not a substitute vote of no confidence.

A planned medical procedure illustrates Section 3: the president transfers power before anesthesia and reclaims it afterward. A president who resigns creates a Section 1 vacancy, so the vice president becomes president rather than merely acting. If the vice presidency itself becomes vacant, Section 2 requires nomination and confirmation by both chambers; the president cannot fill the office alone.

Match the section to the trigger. Death, resignation, or removal creates succession to the office. A voluntary inability uses Section 3. A disputed inability uses Section 4. Misconduct belongs to impeachment, not Section 4, and electoral unpopularity supplies no Twenty-Fifth Amendment mechanism.

Video lesson: Presidential Power: Crash Course Government and Politics #11