But the question in the Michigan case is whether it also protects against political obstructions that make it more difficult for minority students to obtain preferential treatment in college admissions based on race or ethnicity.
“It is exceedingly odd to say that a statute which bars a state from discriminating on the basis of race violates the Equal Protection Clause because it discriminates on the basis of race and sex. Yet that is precisely what the [Sixth Circuit] majority held here,” Michigan Solicitor General John Bursch wrote in his brief to the high court.
“Until now, no court has ever held that, apart from remedying specific past discrimination, a government must engage in affirmative action,” Mr. Bursch said.
He said the case presented a question of "immense importance."
At issue is whether state governments are free to replace race-conscious affirmative action admissions plans with race-neutral alternatives as a means to achieve classroom diversity.
In addition to Michigan, seven other states have undertaken such efforts: Arizona, California, Florida, Nebraska, New Hampshire, Oklahoma, and Washington.
The petition reached the high court at a time when the justices are preparing to rule on whether a race-based affirmative action plan at the University of Texas violates the equal protection rights of white students applying for admission.
There are two different groups that filed suit against Proposal 2. One urged the Supreme Court to take up the case; the other said the justices should not hear the case.
If the court had declined to hear the case it would have permitted the Sixth Circuit decision to remain in full force in the four states covered by that appeals court.
“The vice of Proposal 2 is that it selectively shuts off access to the ordinary political process for advocates of otherwise constitutionally permissible race-conscious policies,” wrote Mark Rosenbaum, a lawyer with the ACLU Foundation of Southern California, in his brief urging the court not to take up the case.