The Declaration of Independence declared that "all men are created equal," but the U.S. Constitution as originally ratified did not live up to that principle. By political necessity it permitted the continued enslavement of blacks and the attendant oppressive system of racial discrimination. Only after the Civil War, with the ratification of the 13th, 14th and 15th amendments, was this defect remedied, and the last two of those amendments were not meaningfully enforced until the culmination of the civil rights movement nearly a century thereafter.

That,...