I was thinking about this in the shower. I think counter to popular opinion, Obama is the one people can identify with more. Minorities can identify with him as a minority, immigrants can identify with his international heritage, the poor can identify with his modest upbringing with a single mother, the upper class with his educational predigree, the intelligensia with his occupation, the Christians with his brotherhood in Christ, other religions with his cross-religious exposure. That still leaves a hole in mid-America, but that's a lot of facets of appeal.