Joe is not going to step down and there are no good mechanisms of replacing him involuntarily. The sooner the Trump opposition realizes this the better.
They are aiming their shots at the wrong target.
They took the wrong lesson from the debate. They saw it and said "Oh shit, he's definitely going to lose, we better abandon him."
They should have thought "Oh shit, he might lose, we gotta work harder to make sure he wins."
Everyone who criticized his performance will fall in line and vote for him anyway. They need to convince the other folks who have been made less sure because of their pointed criticism.
No candidate for president will ever agree to a debate before they have officially secured the nomination at the convention again because of this episode.
http://www.youtube.com/watch?v=F1gWECYYOSo
Please Watch/Share this video so it gets shown in Hollywood.
