So all the front runners for POTUS on both sides of the isle are 70yo+.

Being POTUS is a pressure cooker job and the older one gets the more susceptible to a stroke or heart attack we become.

So what happens after the election and whatever oldster we get has a stroke that reduces that person's abilities? Will the opposing party demand the VP take over? Will the POTUS party try and keep their person in office and try to ignore the reduced capacity, all in the name of their party? Will they accede to having the VP take over? How long would it take for the opposing party to start talking about another election?