A timeline of the cases

July 2000: Parents Involved in Community Schools sues Seattle Public Schools over its use of a racial tiebreaker to assign some students to high schools.

April 2001: U.S. District Court Judge Barbara Rothstein of Seattle upholds the tiebreaker, saying it counteracts the city's segregated neighborhoods and does not violate the preferential-treatment ban of voter-approved Initiative 200.

April 2002: A 9th U.S. Circuit Court of Appeals panel rules 3-0 that the tiebreaker violates the state's I-200. Ballard High Principal David Engle resigns to protest the federal court's decision, saying it will resegregate his school.

June 2002: The federal court withdraws its earlier ruling and says the state Supreme Court should answer the I-200 question. Although the federal court lifts its injunction against the tiebreaker, the school district decides to suspend its use until legal questions are resolved.

June 2003: U.S. Supreme Court upholds the University of Michigan's affirmative-action plan for law-school admissions but strikes down the system for undergraduate admissions.

June 2003: Washington State Supreme Court, in an 8-1 ruling, says assigning students on the basis of race does not violate I-200's prohibition on racial preference, because it affects students of all races in a similar manner. The constitutional question goes back to the federal appeals court.

July 2004: A 9th Circuit panel again rejects the tiebreaker, this time in a 2-1 decision, saying it violates constitutional guarantees of equal protection.

October 2005: The 9th U.S. Circuit Court of Appeals upholds the tiebreaker after an appeal by the district.

December 2005: The U.S. Supreme Court declines to hear a case out of Lynn, Mass., in which parents protested the school district's use of race in student assignment — thereby upholding the district's system.

June 2006: The U.S. Supreme Court agrees to hear the Seattle case.

Monday: The U.S. Supreme Court hears Parents Involved in Community Schools v. Seattle School District, along with a similar case involving the Louisville, Ky., school system.