Over at Whiskey Fire is a clear explanation of why and how the anti-Obama ad about Rev. Wright's sermon is racist.
I'd claim that I couldn't explain it better, but the fact it that I can't explain it nearly as clearly.
The Whiskey Fire discussion displays the fact that most White Racism is unconscious, based on attitudes and training given a child early in life, usually by the child's family. It is a set of mostly unconscious fear-based reactions to people of African descent. Those who hold the Racist attitudes are usually not aware of most of their racist reactions, and resent having it pointed out to them when they display racist reactions.
Those who are the receivers of those racist reactions are normally very aware of the racism they suffer. The open acknowledgment that someone else is acting in a racist manner is not normally itself a racist reaction. It is a recognition of the obvious. The racist person makes different decisions about someone based on their African heritage. That difference is not based on the facts of the circumstances except for the perceived race of the person it is directed at. Only someone unaware of the racist action could possibly consider the reaction and acknowledgment of the obvious racism as itself being racist behavior.
That unconscious irrational reaction to an angry black male is inherently racist. Ann Althouse simply demonstrates her obliviousness to her own racist attitudes when she claims otherwise. To those who are victims of the racism it is very clear that the "Rev. Wright" anti-Obama ad is racist. Only those oblivious to racism could say otherwise.