Back in the 1920s, the intelligentsia on both sides of the Atlantic were loudly protesting the execution of political radicals Sacco and Vanzetti, after what they claimed was an unfair trial. Supreme Court Justice Oliver Wendell Holmes wrote to his young leftist friend Harold Laski, pointing out that there were "a thousand-fold worse cases" involving black defendants, "but the world does not worry over them." Holmes said: "I cannot but ask myself why this so much greater interest in red than black." To put it bluntly, it was a question of whose ox was gored. That is, what groups...