lines may be drawn. My guess is, if it were ever tested, the SCOTUS would be dropping everything it has on the plate until that question is answered in a hurry.

I also imagine there is a difference between "taking the keys from Grampa" because the Cabinet and perhaps a conniving VP has lost faith in him (which is more like a "coup") vs. Grampa is in the driveway and if we don't do something right away he's going to drive the car right into a crowd full of people (which is more like a temporary restraining order while the substantive issues get litigated). I'm a lot more comfortable with the latter than the former, but the mechanism is there and my read on it is that it authorizes exigent removal of the POTUS for any number of reasons that may be warranted. The ultimate question of what "unable to discharge duties' means would be up to SCOTUS and completely novel.

An interesting point you touched on is to what extent character or malintent could play into it. For example, could it cover a criminally dishonest president who is about to sell out the country to a foreign adversary, even if he's perfectly sane? I don't see why not. Could it include a president who has gone full authoritarian and started commanding that all his adversaries be rounded up and jailed? Again, I don't see why not.

I find it sad that history is at a point where this is even being discussed at all outside the context of a stroke. I also wonder whether it's been used "covertly" before. Like, for example, who was really running the country during Reagan's last two years in office? Who knows, but almost certainly not him.