Last weekend, I read the fascinating book The Political Brain, by Drew Westen.  Drew is a trained psychologist, and believes the "theory of mind" political professionals who work for Democrats have developed is totally, utterly wrong.  To simplify his thesis, no voters(not even well-educated ones) make voting decisions by rationally weighing where the candidates stand on the issues.  Instead, people begin with their emotional feelings towards a candidate, and then rationalize reasons why they support a given candidate.

I think it tells us a lot about what has gone on during this primary fight...