To make the earlier post on the three theories of voter behavior -- policy-oriented, projection, and persuasion -- a bit more concrete, my sense is that the Democratic primary, at least as it's playing out among high information voters, has actually broken down neatly into a demonstration of each.
Edwards has gained a lot of rather unexpected support from policy-oriented types -- voters who are surveying the range of candidates and seeing whose white papers conform most closely with their preferences. Want the most radical health care plan you can find? Edwards is your guy.
Hillary, by contrast, seems to trigger a lot of projection. I can't tell you how many of her supporters have tried to convince me that she's really much more liberal than she comes off, but has been forced into displaying a centrist, hawkish streak because of the demands of running as a woman in a traditionally masculine sphere. Her supporters seem to spend a lot of time convincing themselves that she's really very progressive, and appearances to the contrary are misleading.