I have a serious question for anyone who can answer it. What happens to control of the military (which presumably includes the nuclear forces) should the President become incapacitated, for example by a stroke? I have read the 25th Amendment, but I can easily envisage situations where executive authority needs to be exercised without the luxury of time in which to invoke its provisions. What happens then?

This sort of question became relevant when a two-hour war became possible. In former times, there would always be time to gather the relevant people; this might now conceivably not be the case.