The US Constitution provides instructions for how to remove a president from office if they are unfit to do their job—gravely wounded, for example, or mentally unstable. The instructions were ratified as an amendment in 1967, after John F. Kennedy's assassination. Until that point, the Constitution just vaguely referred to the fact that a president could be removed for "Inability to discharge the Powers and Duties of said Office." When can the 25th amendment be invoked for an unfit president? Whenever the vice president and a majority of the Cabinet are ready to do so. One anonymous "senior official" wrote...