Correction: An earlier version of this editorial mischaracterized Abigail Fisher’s legal challenge to the University of Texas’s admissions policy. She argues that the policy is unconstitutional because it explicitly permits consideration of race during the admissions process. The following version has been revised.

March 3, 2012

ABIGAIL FISHER did not have much luck when she applied to the University of Texas (UT) at Austin in 2008, but last month she succeeded against much longer odds: The Supreme Court agreed to hear her case.

Ms. Fisher sued the university, arguing that its use of race-based factors — or factors that serve as proxies for race — offended the Constitution’s promise of equal protection and violated the Supreme Court’s admonition that only “narrowly tailored” programs that pass the most rigorous legal test may be employed.

The Texas system guarantees admission to students who graduate in the top 10 percent of their high schools’ senior classes. Some 75 percent of those admitted as freshmen to the school in Austin each year have come from this pool, which has helped UT make great strides in increasing minority enrollment, which hovers between 18 percent and 20 percent.

The school decided that students who filled the remaining slots should reflect the state’s growing diversity. UT took into account several factors in addition to grade-point average and SAT scores, including whether an applicant came from a one-parent household or one where more than one language is spoken. It also decided to identify each student explicitly by race and use that to ensure campus-wide diversity. Ms. Fisher cites this last consideration as constitutionally problematic.

A federal appeals court, however, concluded that Supreme Court precedent allowed the university to use such programs to achieve the “compelling interest” of diversity in higher education.

The high court most often weighs in to resolve issues when appeals courts disagree. There is no such “circuit split” in this case, which, moreover, applies to only three states — Texas, Louisiana and Mississippi. Has the court taken this case to narrow or possibly overturn recent decisions upholding affirmative action? Ms. Fisher has not asked for that, and we hope the court refrains from issuing such a result.

As recently as 2003, the court acknowledged the importance of carefully crafted diversity efforts in higher education. If the court finds fault with UT’s unique approach, it should keep its ruling narrow to address only those instances in which the university may have overstepped existing law. The justices shouldn’t use Ms. Fisher’s case to erode or reverse the modest affirmative action efforts allowed by law.