In 1954, the Supreme Court unanimously ruled that students could not be assigned to public schools solely because of their race. This past week, a deeply divided high court ruled, 5 to 4, that this is still the case.

But the social context has changed dramatically over the intervening 53 years. Back then, the racial criterion was a tool to keep black and white students apart. Now, school districts, often pursuant to court orders, assign on the basis of race to ensure that black and white students attend school together.

However, wrote Chief Justice John Roberts for the majority: “Simply because the school districts may seek a worthy goal does not mean they are free to discriminate on the basis of race to achieve it …'”

The heart of the Constitution’s guarantee of equal protection, he wrote, is that government must treat its citizens as individuals and not as members of a particular, in this case, racial, class.

In the abstract, this is fine, but Roberts’ practical formulation is of little help to school officials wrestling with more invidious forms of segregation. Wrote the chief justice: “The way to stop discrimination on the basis of race is to stop discriminating on the basis of race.” It is, as the expression goes, easy for him to say.

The progress since Brown v. Board of Education kicked the legal props out from under a shameful racial construct has been slower and more uneven than its advocates had hoped, but there has undeniably been progress.

The nation — and the courts — must still address the problem of racially isolated big-city schools that can’t seem to teach and students whose social pathologies have left them ill-equipped to learn.

Justice Anthony Kennedy, the court’s swing vote, concurred, skeptically, almost reluctantly, writing that if the majority opinion is taken as permission for school districts to ignore de facto resegregation and if the opinion “suggests the Constitution mandates that state and local school authorities must accept the status quo of racial isolation in schools, it is, in my view, profoundly mistaken.”

It is of profound importance to a diverse nation, committed to equality of opportunity, that these views not be mutually exclusive