There are two very important ideas that emerge from Justice Kennedy's concurring opinion in Parents Involved, the landmark school desegregation opinion handed down today. Because of the way the remaining justices split their votes, it's Justice Kennedy's concurrence that really tells us what "the law" says going forward. Kennedy's first important idea is that school segregation and racial imbalance is no longer a white-nonwhite dichotomy. In a city with substantial racial diversity, a school with 50% white students, 50% African American students, and no Asian or Latino students, is not racially balanced. The defendant school districts lumped all students of color together in assessing racial imbalance, and Seattle did not permit individual students to be classified as members of multiple racial groups for school assignment purposes. Justice Kennedy sensibly argues that school districts must do better, and use finer-grained racial classifications if they are to use them at all. I believe that this part of Kennedy's opinion will be uncontroversial within a few years, if it isn't already.
Justice Kennedy's second idea ought to be more controversial, and it is certainly more intellectually ambitious.