If Obama loses, it will because Dems are racist. If Clinton loses it will be because Dems are sexist. Two bloggers I like, Sharon Cobb, and Tennessee Guerilla Women, are having a disagreement. It is possible that if Dems don't start playing nice that they will implode and McCain will be president in November.
I would hope that the Dems just get happy with which ever candidate wins the nomination. I like Obama, but if he doesn't get it, then I am with Clinton. I hope those who are for Clinton will accept Obama if he wins the nomination.
Remember good Molly's advice:

Either will be better than McCain.