How to replace a demented candidate 101: (only use strategy after you realize they're headed for sure defeat)
1- Roll them out in front of the nation, at a debate, to show they are unstable.
2- Finally discuss the instability as if it's this new thing. This will help to make the change easier for people to swallow.
3- Hold press conference to show, yet again, how disconnected they are.
4- Do what's "right" for the good of the party and constituents and remove and replace. In the name of saving democracy, of course.