What is racism?

I know it's considered racist not to vote for someone solely on the basis of their skin color. But, is it also racist to vote for a person solely on the basis of their skin color? Consider this statement from a supposedly conservative black talk show host regarding Barack Obama: "I don't necessarily like his policies; I don't like much that he advocates, but for the first time in my life, history thrusts me to really seriously think about it," Armstrong Williams said. "I can honestly say I have no idea who I'm going to pull that lever for in November. And to me, that's incredible." To me, that's not only incredible, it's racist! It means putting race ahead of common sense and your own convictions, as well as discriminating against a more highly qualified candidate of a different color. People should be judging candidates on the merits of how well they match up with their own beliefs, not on skin color (unless two candidates are equal in every way except race.) Until everyone starts doing that, I think this country is still racist.