This fall, the Supreme Court will consider the constitutionality of raceconscious K-12 student assignment policies. At a time when schools nationwide have become more racially isolated, some districts have used such policies to mitigate segregation. This article examines these policies in light of the Supreme Court's recent decisions concerning affirmative action at universities. It explores the legal implications of differences between higher education and K-12 schooling, considering what the differences might mean for particular diversity goals and for policies designed to meet those goals. Beginning with a concise summary of research on the effects of K-12 student diversity, the article places the research in a current legal context, explaining relevant law, what the courts consider important, and how research addresses evidentiary issues.