SEATTLE -- The Supreme Court is set to hear a case today filed by a predominantly white parents' group from an affluent Seattle neighborhood. Their children were denied admission to a majority-white school, and instead assigned to mostly minority schools.

The case, dating to 2000, has become a lightning rod for critics who say school boards go too far to try to achieve an elusive goal of racial integration. The court's rulings on Seattle and a similar case involving Louisville, Ky., schools are likely to affect hundreds of districts nationwide that use race as a factor in school assignments.

But a close look at Seattle shows that officials have frequently yielded to school-assignment pressure from white parents in pursuing another elusive goal -- middle-class participation in public schools.

In 2004, after the district scrapped race as a factor in assignments because of the legal threat, another group of white parents from the same neighborhood got upset when their children were passed over at the same majority-white school, Ballard High. They were left out not because of race, but because they didn't live near enough.

This time, the school district quietly backed down when the parents started sending their children to private or suburban schools instead of the struggling, majority-black school to which they'd been assigned. Ballard and other supposedly full schools together took about 100 extra students, most of them white.