But for some people, what happens if he falls seriously ill is top of mind. The White House doctor has maintained that Mr. Trump will continue carrying out his duties “without disruption,” but there are protocols for when a president becomes unfit to perform the role.
The government’s continuity plan in case of a national emergency, which largely focuses on wide-scale attacks, outlines such a procedure. The presidential line of succession, laid out in a 1947 law, puts Vice President Mike Pence first in line to replace the president and the House speaker, Nancy Pelosi, second.
A point of contention, however, is that the Constitution does not offer clear guidance on how to determine whether a president is unable to perform the duties of office.
The 25th Amendment was intended to deal with any ambiguity about who leads the government when a president cannot. If the president becomes sick and the cabinet determines that he or she is unable to perform the office’s duties, the 25th Amendment grants the administration the power to temporarily transfer authority to the vice president. The president can then, once he deems himself or herself fit, reclaim the power of the presidency.
Other U.S. presidents have fallen seriously ill while in office — George Washington was feared close to death during a flu outbreak and Woodrow Wilson was gravely ill during peace talks after World War I in Paris — and four have died of natural causes while in office. Four others were assassinated.
But not since 1981, when President Ronald Reagan was shot, has a president been known to confront a life-threatening illness in office.