There is a recurrent theme in American history: the clawing back of hard-won progress. And the Supreme Court last week used the most specious of arguments to do so with affirmative action.

In the majority opinion, Chief Justice John Roberts wrote that affirmative action — in this case, the use of race as a factor in university admissions — cannot stand because “eliminating racial discrimination means eliminating all of it.” But, of course, neither the court nor America itself has any desire to eliminate all of it. Reading that line was like having someone spit in my face.