Clinton is out with long knives for the Messiah....He is telegraphing to his and Hillary’s supporters that it is ok to vote McCain//Palin. Hillary will not attack Palin, and Bill will help Barry as little as he can get away with. They see Barry is drowning and they are not about to throw him a life vest.
As for Hillary replacing Lpugs Biden on the ticket, I do not think there is any way she would do that. No upside for her, and lots of downside risk. If she accepted that and Obama still lost, she would be stained just like the Silky Pony was in the last election.
HRC won't take second place. Her return to power requires that the absolute defeat of the Obama-Dean-Brazile-Pelosi-Reid DNC coupsters. Obama's personal defeat and any downstream effects will help HRC purge D party non-HRC apparatchiks.
The guerilla war within the D party has just begun. Watch the lugnuts start slowly flying off their wheels.