Lets say Biden becomes the official Dem candidate at the 2020 Democratic National Convention, is there a way to get a different candidate if Biden goes senile? How to get a different candidate after the Democratic National Convention? I can't find how that would work. I guess it has never happened. But there is a very real possibility Biden cannot be on the ballot - Burisma, health, DNC email hack, Russia, Russia Russia, Ukraine, etc. The whole ex Obama team could go down.