We know this because there is no constant idea of "black" or "white" across time or space. We know this because Charlie Patton fathered the blues, and Alessandro de Medici ruled in Venice. Black in America is not black in Brazil, and black in modern America is not even black in 18th-century Louisiana. Nor are people we consider "white" today any sort of constant. Throughout American history it has been common to speak of an "Italian race," an "Irish race," a "Frankish race," a "Jewish race" even a "Southern race." One might take a hard look at Williamson's agreeable portrait, for instance, and note the problem of assigning anyone to a race. "Race," writes the imminent historian Nell Irvin Painter, "is an idea, not a fact."
In this country, at this moment, "African-Americans" are an ethnic group comprised of individuals of varying degrees of direct African ancestry. Nothing about this fact necessitated plunder or injury, and it is the injury—through red-lining, black codes, slaves codes, lynching, ghettoization, fraud, rape, and murder—with which reparations concerns itself. The point is not "racial apportionment," which is to say giving people things because they are black. It is injury apportionment, which is to say restoring things to people who have been plundered.
Racism, and its progeny white supremacy, is concerned with dividing human beings, on the basis of ancestry (which is very real) and slotting them into a hierarchy (which is an invention). "Race" is that hierarchy—and any study of the word across history bears out its relationship to assigning value and scale across humanity. In polite society we've moved past overtly hierarchal ideas about "race," but the problem of imprecise naming remains with us. Let us bypass that imprecision—the Anglo-American tradition which Williamson extolls has, as he concedes, sought to erect and uphold a racist hierarchy. Reparations seeks its total and complete destruction.
Williamson believes that reparations must either boil down to a "symbolic political process" or a series of polices that helps America's poor and disproportionately aids African-Americans. How, Williamson asks, can one make a claim on behalf of Sasha and Malia Obama, in a world of poor whites? In much the same way that a factory which pumps toxins into a poor neighborhood is not indemnified because a plaintiff rises to become a millionaire. Taking Williamson's argument to its logical conclusion, a businessman brutalized by the police should never sue the city because, well, homelessness.
People who are injured sometimes achieve great things—this does not obviate the fact of their injury, nor their claim to recompense. Warren Moon achieved more than the vast majority of white quarterbacks. Had racism not forced him into the CFL for the first five crucial years of his career, he might have had more success than any quarterback to ever play the game. Satchel Paige enjoys an honor which the vast majority of white baseball players shall never glimpse—induction in the Hall of Fame. What might Paige achieved had he not been injured by white supremacy for the vast majority of his career? Mr. Clyde Ross is a homeowner, and considerably better off than many of his North Lawndale neighbors. To achieve this he worked three jobs and lost time that he should have been able to invest in his children. What might Mr. Ross have been had he not endured racist plunder from Clarksdale to Chicago?