A public university, the U.S. Supreme Court has rightly ruled, has a compelling interest in admitting students diverse enough to dispel racial and ethnic stereotypes and thereby add to the education of all students. The admissions policy a university uses in pursuing that diversity, however, must be "narrowly tailored."

In the cases at hand, the University of Michigan scored one out of two.

Its law school admissions policy passed muster with five of the nine justices. Its undergraduate policy flunked with six of the nine. And so diverse was the reasoning of the justices – 150 pages of decisions and concurring and dissenting opinions – that only this much is readily apparent:

A public university may weigh the racial or ethnic status of minority applicants, but it must do so in a context and by a process far more complex than simply adding 20 points for the "soft variable" of race to the "score" of every minority applicant. That's how the policy at Michigan's undergraduate school worked, and how admissions policies may work no longer, according to the high court.

The law school policy fared better. Membership in "a minority historically discriminated against" may weigh substantially among other elements of diversity, or not at all. It may be neither automatic nor predetermined, only "a potential 'plus' factor."

That is, as the university's president put it, an endorsement of "the principle of diversity." Indeed, Justice Sandra Day O'Connor, writing for the majority, made clear that the court has now "endorsed" this view, initially expressed in the landmark 1978 Bakke decision by Justice Lewis Powell alone.

Yet this ruling hardly resolves fully the issues of racial preferences or quotas. Like the court's ruling that groups' ads hawking political candidates can't say "vote for," this ruling continues preferences and quotas if wrapped in subtlety. And it may in fact perpetuate them.

While universities may not set "quotas" for certain minority students, the Michigan law school apparently may continue to seek a "critical mass," a number sufficient to ensure that minority students are neither isolated in the classroom nor representative of a single viewpoint. Who determines that number, and how?

"Narrow tailoring," O'Connor acknowledges, does "require serious, good faith consideration of workable race-neutral alternatives that will achieve the diversity the university seeks" – but then gives those alternatives short shrift.

Racial preferences, she acknowledges, are a "deviation from the norm" of equal treatment. But the "individualized inquiry into the possible diversity contributions of all applicants" in the law school's race-conscious policy "does not unduly harm nonminority applicants."

And "mindful" that ending racial discrimination is a "core purpose" of the 14th Amendment, she merely states that "race-conscious admissions policies must be limited in time." Universities may hasten that day by looking to the race-neutral policies of universities in California, Florida and Washington. And the court expects, "25 years from now," universities will no longer need racial preferences.

But after half a century of them, the Supreme Court's approval of them and a cohort of lawyers who are lawyers because of them, who will end them? And how? "Baffled and divided," O'Connor said of the lower courts who have disagreed on these issues. Baffled and divided the nation remains.