One of the greatest mistakes that we make as Democrats time and time again is assuming that the majority of the electorate makes decisions the way we in Left Blogistan do...that they study policy, records, and position papers before making an informed decision about a candidate.
We are wrong. George Bush didn't get elected because of his policies. He got elected because he was "compassionate" and apparently most of the country wanted to drink a beer with him (although now, I'd imagine most of those people would throw a Busch in Bush's face if they had the chance.)
Most voters go for the emotional connection - the fire in the belly, the personal connection (I have young kids, he has young kids, so he must understand), the thinking that he might just be like me.