I'm going to take a little leap here. Well, actually, it doesn't seem like a leap to me. It seems depressingly obvious. Here's my prediction for next prez.
The Man has played the social system again. Women vs. Blacks. Sexism vs. racism. Hierarchy of oppression, bell hooks be damned.
So regardless of who wins the Democratic nomination, people are going to vote "personality not party", and McCain is going to win because many who typically vote Democrat will be buying into the racism and sexism and thinking their feeling really is about the candidates.
Yeah, people are sick of Republican government at this point, but they think McCain is different, so this will be a different Republican administration. Forgetting that McCain the individual comes with a whole bunch of other Republicans who will be advancing the usual Republican ideals and goals.