The best hope for the GOP is a stalemate at the DEM convention. Its a narrow hope, and its one that the GOP has no control over.
However, if the delegate count is close enough, with a slight Obama lead, but the superdelegates go to Clinton, then the dems will splinter badly. You see, democrats are racist at heart. If Clinton steals the election from Obama, blacks will cross-over to spite her. If Obama wins, some hispanics will cross over to McCain.
Another way of looking at that is the Dems VP choice. If Hillary wins, if she doesn’t pick Obama as VP she will really anger Obama’s black supporters and others who got excited about them running together at the last kissyfest debate. Down side for her if she does pick him is he will get more media attention than her and is a much better orator. She can’t stand being upstaged by anyone.
However if he wins I don’t think he needs her at all, and by not choosing her I don’t think he will do his run too much harm.