The precise ancestry of a black drug dealer or cop killer is irrelevant. His blackness predicts and explains his crime. He reinforces the racist presumption. It is only when that presumption is questioned that a fine analysis of ancestry is invoked. Frederick Douglass was an ordinary nigger while working the fields. But as a famed abolitionist, it was often said that his genius must derive from his white half.

We Were Eight Years in Power: An American Tragedy