"The problem is what is called mismatch," said Heriot. "As a result of affirmative action, black students in particular, Hispanic students as well, are likely to go to a school where their entering credentials put them towards the bottom of the entering class," at top schools like Harvard or Texas. Their lower grades as a result, said Heriot, mean those students are much more likely to give up on the ambition to major in science, or go into medicine or the law.

"It's heartbreaking," she said. "If only the students would go to the school where their entering credentials are pretty much in the middle or towards the top of that particular college."

Many social scientists and civil groups, including the NAACP, reject that analysis.

"I think those studies and arguments don't really jive with the real world," said Adegbile. "The admissions officers are best situated to make the determination and some of the tradeoffs, to have a mix of students that can accomplish all of the things that college and universities are engines to do."

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The high court has had an evolving record on the discretion of state officials to decide who attends their institutions.

The justices in 2003 said state universities can narrowly tailor their admissions policies to consider an applicant's race, to achieve a "critical mass" of minority students. But they reaffirmed existing limits -- bans on the use of quotas, extra "race" points in selective criteria, or "balancing" measures to reflect the larger population.

That landmark case from the University of Michigan is the subject of current but separate appeals over a state ballot measure designed to eliminate any racial criteria. A divided federal appeals court last year concluded the voter-approved ban on "preferential treatment" at public colleges and universities was unconstitutional, and "alters Michigan's political structure by impermissibly burdening racial minorities."

The Texas case is complicated over the issue of "standing" and whether Fisher should even be allowed to bring her lawsuit. She graduated this spring from Louisiana State University, where she went after being rejected by the University of Texas -- and school officials had argued she has no "live" controversy or claim necessary for the high court to intervene. They said her only "harm" would be trying to recoup nonrefundable application fees.

Through her lawyers, Fisher said she did not want to be interviewed by CNN.

In accepting the case, the high court made no mention of whether the standing issue would affect its ultimate ruling. The court also announced Justice Elena Kagan will not participate in the case since she apparently had been briefed on the issue as the Obama administration's solicitor general before joining the high court.

That leaves the possibility of a 4-4 ruling, meaning Fisher would not prevail, and leaving undecided the larger constitutional questions presented.

Fisher's attorneys made the strategic decision to sue as an individual instead of bringing a class-action discrimination claim, which would have made it easier in some respects. A co-plaintiff, Rachel Michalewicz, dropped out of the suit last year.

The university proudly touts its diversity: the latest freshman class is about 46 percent white, 25 percent Hispanic, 18 percent Asian, and 5 percent black.

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The Michigan case was divisive in 2003, with Justice Sandra Day O'Connor the swing vote. "In order to cultivate a set of leaders with legitimacy in the eyes of the citizenry, it is necessary that the path to leadership be visibly open to talented and qualified individuals of every race and ethnicity," O'Connor said. "The (Michigan) Law School's educational judgment that such diversity is essential to its educational mission is one to which we defer."

But she left the bench in 2006, replaced by Justice Samuel Alito, who is expected to strongly question the Texas policy.

Justice Clarence Thomas was among four conservative justices who found the Michigan policies unconstitutional. "The Law School, of its own choosing, and for its own purposes, maintains an exclusionary admissions system that it knows produces racially disproportionate results. Racial discrimination is not a permissible solution to the self-inflicted wounds of this elitist admissions policy."

Despite that high court ruling, some states, including California, do not allow race considerations in college admissions. The issue now before an arguably more conservative high court is whether the Texas policies should be re-evaluated, as states have had nearly a decade to re-evaluate such diversity considerations.

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A final word about Sweatt. When the Houston mailman applied to the University of Texas in 1946, no African-American at the time could be admitted to any law school in the state, and there were even no black-only law schools. So a purported "separate-but-equal" government policy was in fact "separate and non-existent."

School administrators cited the established white-only policies for their rejection -- "Texas' wise and long-continued policy of segregation," in the state attorney general's words -- and instead offered Sweatt an out-of-state scholarship. He refused and took his case to court.

By that time the state had agreed to create a blacks-only School of Law of the Texas State University for Negroes -- in Houston, not Austin -- but its implementation was delayed for many months. The high court unanimously found in favor of Sweatt -- concluding the separate school for a variety of quantitative and intangible reasons lacked "substantive equality." He became the first African-American ever ordered admitted to an all-white institution.

His legal victory was an important landmark -- a building block that culminated three years later in the 1953 Brown v. Board case, where the justices ordered a permanent end to state-mandated public, racial segregation.

Sweatt's personal victory was bittersweet. He entered the UT law school, but later dropped out, following ill health as well as hostility from white classmates. He died in 1982, and the Travis County civil courthouse in Austin was renamed in his honor.