A lot of white people are uncomfortable with voting for a black person who acts black, for lack of a better term. If the black candidate has a bunch of social facts signifying that he or she is part of white American culture (which a lot of us honkeys tend to think of as just plain American), the skin isn't as big an issue.
So while it's fine for Bush, Clinton, etc. to have regional dialects, even ones associated with poor or working class people, a black presidential candidate would have to speak Standard English the whole time. Biographical details like Condi Rice playing the piano help, too.
It matters that Powell and Condi Rice are both foreign policy specialists. Technocrat good, populist bad. A black political figure whose calling card is advocacy of the inner-city poor and working classes, who are mostly minorities? That's kind of scary to a lot of white people; if a politician is making decisions primarily with "those people" in mind, it might come at the expense of middle class suburbanites.
Anthony Williams is a very good example of a black politician who gets support from white voters. He was elected on the basis of being an egghead who would sort out DC's finances.
Surreal said:
He looks like a good man. That's what we need really. Someone with a clear head that knows what is good for the country.
This sounds like a good idea, but it's a pretty bad one.
The picture you're going to get of a politician's personality is going to be very incomplete, and very skewed. There are issues where people of integrity, courage, and morals, defined any number of ways, are going to disagree. You have to first make sure the person you're voting for you agrees with you generally on the things that you find to be important.
You absolutely should not buy the media's portrayal of someone as having good character, or use a third-hand judgement about personality as the main criterion for electing someone.
The desire for a Good Man to take care of everything and make the hard decisions is understandable, but in a democracy, the responsible thing is to educate yourself, make up your own mind, then support whoever matches your own opinions.