Pew recently conducted a pretty fascinating survey in which they asked registered voters to evaluate the presidential candidates in terms of their ideological positions. Check out this graph:
Among Democrats, Edwards is perceived to be the most conservative. Both Republican and Democratic respondents agreed with this ranking. This is fascinating because, if you've been listening to the guy talk about the war or about poverty, you know that he's probably the most liberal of the leading candidates. All this testifies to the power of demographics. Voters look at Edwards and see a white male with a southern accent - they infer that he's more moderate than the female or black candidate.
This is a totally unfair advantage for Edwards, but it is what it is. And what that means is that the party could nominate him and get the liberal policies it wants without most voters thinking the Democrats have gone socialist.