Just for fun: Bush Withdraws

OK, OK, I know this is wishful thinking beyond belief, but I thought it might be fun to play with this. Let's say that this gets even uglier for shrub (and, indeed, it seems to be getting uglier by the hour), the smoking Blue Dress turns up, and Bush decides not to stand for reelec, er, election.

First, does has anyone else been having the same dreams?

Second, how would this play out? Back in '68, Johnson's announcement that he would not run didn't come until March 31. But, of course, the primary season was much later. That year, Bobby Kennedy didn't even announce his candidacy until March 16 and died on June 4, the night of the California primary.

Third, who would likely get the nomination. My first assumption is that Dick Cheney is too damaged to even consider trying.

Any ideas here? Does anyone even want to get into this line of thought?