"Michigan cannot force those advocating for consideration of racial factors to traverse a more arduous road without violating the Fourteenth Amendment," the court said. "We thus conclude that Proposal 2 reorders the political process in Michigan to place special burdens on minority interests."
In dissent, Judge Danny Boggs said the majority relied on an "extreme extension" of two Supreme Court cases to justify its decision, one in 1969 involving the repeal of a fair housing law in Akron, Ohio, and the other in 1982 involving an effort to stop racial integration in Seattle schools.
"We have the citizens of the entire state establishing a principle that would in general have seemed laudable," Boggs said of Michigan.
Another dissenter, Judge Julia Smith Gibbons, said the will of 58 percent of voters in 2006 has been shredded.
"Michigan has chosen to structure its university system such that politics plays no part in university admissions at all levels. ... The Michigan voters have therefore not restructured the political process in their state by amending their state constitution; they have merely employed it," Gibbons said.
Besides Michigan, six states have banned racial preferences in admissions: Washington, Nebraska, Arizona, New Hampshire, California and Florida. In Texas and Georgia, leading public universities use a race-neutral system, though the University of Texas has maintained some use of affirmative action.
Since a 2003 Supreme Court decision, universities have been allowed to use racial preferences if they choose, though they are not compelled to do so. The court last month heard arguments in a case that could change that precedent. Abigail Fisher, a rejected white applicant, is suing the University of Texas.
AP Education Writer Justin Pope contributed to this report from Ann Arbor, Mich.