Probably the parties and their donors would scramble to replace them.

Harris has a leg up as she would be promoted to President and would be the incumbent. But she might not be prepared for a primary. Probably Gavin Newsom, her and a couple people would fight over some key endorsements and donors.

Well Chris Christie and Mike Pence would probably kick themselves as they just dropped out of the race. In a lot of ways, the republican race wouldn’t change much. At least Nikki Haley and Ron DeSantis would still be fighting over the voters not waiting for Trump to resurrect three days later.

The really dicy shit happens if the winning candidate dies before inauguration.