The question did not get proper constitutional attention until Congress, in 1965, passed the Twenty-fifth Amendment, which two years later was ratified by the required three quarters of the states. The most pressing issue at the time was dealing with the Vice-Presidential vacancy that occurs after a President’s death, as had happened when Kennedy was murdered, in 1963; Lyndon Johnson had been without a Vice-President until after the 1964 election. The amendment let a President appoint a Vice-President, though only with a majority vote in both houses of Congress. (This rule was first applied in 1973, when President Richard Nixon nominated Gerald Ford to replace Vice-President Spiro T. Agnew, who’d been forced to resign in a bribery scandal.) It even dealt with a President being briefly out of commission, as George W. Bush was in 2007, when he underwent a colonoscopy and transferred power to Vice-President Dick Cheney for the duration of the procedure.

The issue addressed by Eisenhower—the problem of transferring power to a Vice-President if a President is incapacitated, and of the President taking it back when he feels ready—was spelled out in Section 4. The machinery moves slowly: a Vice-President, with a majority of either the Cabinet or of Congress, may inform the Speaker of the House of Representatives and the president pro tempore of the Senate, in writing, that the President “is unable to discharge the powers and duties of his office.” In that case, the Vice-President takes over as “Acting President.” But if the President objects—declaring in writing “that no inability exists”—it gets complicated: then the Vice-President and a majority of the Cabinet, or of Congress, have to tell the Speaker and the president pro tem that the President can’t do his job. Then it’s up to Congress, which would have forty-eight hours to meet, twenty-one days to decide, and then to vote, by a two-thirds majority, on whether to give the President’s powers to the Vice-President—hurdles that would protect the Presidency from a seizure of power but, in case of a Strangelovian emergency, would be unrealistic.

That Eisenhower-to-Nixon memorandum, dated February 5, 1958, was shown to only a few people, but it was leaked. When Eisenhower, in March, was asked about it at a news conference, he said, “We are trying just to say that we are trying to carry out what normal humans of good faith having some confidence in each other would do in accordance with the language of the Constitution.” As to whether these transfers of power could lead to “a sort of musical chairs,” he replied, “I think it means when the inability is removed he resumes his duties,” although he saw the potential problem it posed. He said, “I admit this: if a man were so deranged that he thought he was able, and the consensus was that he couldn’t, there would have to be something else done, no question.”

The application of all of this to the present age may sound like a TV melodrama. But then the same might be said of what the nation has experienced during the past year or so. If Presidential incompetence, or unfitness—or, to use Ike’s word, derangement—ever became a clear and present danger, it would take more than an inventive scriptwriter to head off a disastrous turn of the heretofore fortunate American narrative.