AMID the  ceaseless and cacophonous debates about how to close the achievement gap, we’ve turned away from one tool that has been shown to work: school desegregation. That strategy, ushered in by the landmark 1954 Supreme Court decision in Brown v. Board of Education, has been unceremoniously ushered out, an artifact in the museum of failed social experiments. The Supreme Court’s ruling that racially segregated schools were “inherently unequal” shook up the nation like no other decision of the 20th century. Civil rights advocates, who for years had been patiently laying the constitutional groundwork, cheered to the rafters, while segregationists mourned “Black Monday” and vowed “massive resistance.” But as the anniversary was observed this past week on May 17, it was hard not to notice that desegregation is effectively dead. In fact, we have been giving up on desegregation for a long time. In 1974, the Supreme