I used to think the explanation for this behavior was "group think", know I realize they want a savior, someone to make them feel good and to save them.  They will not make a decision until there is no choice, because it does not really matter who they choose, as long as it is the one that other's like them choose.  President Clinton taught us all, that as soon as the people delude themselves that much, he could go against everything they believe, and they would never hold him responsible.

I would like to encourage this behavior, because when their candidate finally wins (most likely Hillary Clinton in 2008), that person will find out that they can agree with conservatives so more people will like them.  After all, they will never loose the support of the deluded masses yearning to feel good about themselves.