If Melvin Urofksy proves anything in his new history of affirmative action, The Affirmative Action Puzzle, it’s that there is little to say about the policy that has not already been said. From the start, the basic terms of the debate were set: Critics appealed to colorblind fairness and defenders to “compensatory justice” — which, Urofsky observes, was used as a synonym for affirmative action in its early days.

Then, a strange thing happened: Defenders of affirmative action changed their argument. Gradually, they stopped appealing to historical injustices and instead began arguing that racial diversity is good for its own sake. By the early aughts, Urofsky observes, slavery and Jim Crow were rarely mentioned in defenses of the policy.