Most Americans are familiar with the 1787 compromise that sought to bring North-South equality to Congressional representation by counting slaves as three fifths of a person, or three fifths of a white person — but then, as genetic testing has demonstrated, most Americans are familial to that compromise as well. America’s genetic material is a melting pot of the African, European, and Asian — to say nothing of the Navajo, Cherokee, and Sioux, the country’s original Other.

The three-fifths calculation wasn’t precise, of course, but at least it was simpler than the calculations for deriving the status of an “octoroon” or…