WASHINGTON -- The Supreme Court Monday agreed to hear a second case involving affirmative action in higher education -- even before it has issued a ruling on the other case that it has considered this term.

The justices agreed to consider whether Michigan voters in 2006 had the legal right to bar the state's public colleges and universities from considering race or ethnicity in admissions. Should the Supreme Court invalidate that vote, bans on the consideration of race by public colleges in other states -- most notably in California -- could also be thrown out.

The U.S. Court of Appeals for the Sixth Circuit -- in two rulings, one by a 2-1 vote and one by an 8-7 vote -- found that Proposition 2 (the measure passed by Michigan voters) was unconstitutional. But those rulings have been stayed, pending this appeal.

The argument advanced by the civil rights activists who filed the challenge to the Michigan referendum is not strictly speaking on the merits of affirmative action. Rather, they argue (and the appeals court has agreed) that Proposition 2 effectively denied minority citizens the same right to influence the policies of public universities that other groups have. So, for example, if rural Michiganders want to encourage the public universities to adopt policies that would help rural students, they can do so. But under Proposition 2, those who believe that consideration of race is important can no longer try to get the public universities to do so in admissions. Proponents of Proposition 2 have said that the referendum is a race-neutral tool of democracy, and that states have the right to use referendums to consider policies with regard to public college admissions policy.

Other courts have rejected attempts to invalidate statewide votes to bar the consideration of race in admissions. Last year, the U.S. Court of Appeals for the Ninth Circuit rejected a suit challenging California's statewide ban on the consideration of race and ethnicity. Both the California and Michigan challenges were brought by a group known as the Coalition to Defend Affirmative Action, Integration and Immigrant Rights and Fight for Equality by Any Means Necessary, an organization known as BAMN (the acronym for the end of its name).

The Michigan case is known as Schuette v. Coalition to Defend Affirmative Action. Bill Schuette is the attorney general of Michigan and is the one who appealed the Sixth Circuit's ruling to the Supreme Court. SCOTUSblog has many of the briefs in the case available here.

The first affirmative action case before the Supreme Court this term is Fisher v. University of Texas at Austin, in which Abigail Fisher, a white woman rejected for admission by the university, said that her rights had been violated by UT-Austin's consideration of race and ethnicity in admissions decisions. Fisher's lawyers argued that the University of Texas need not consider race because it has found another way to assure diversity in the student body.

Texas uses a "percent plan" -- in which roughly the top 10 percent of high school graduates are guaranteed admission to the public university of their choice in the state. Because many Texas high schools are almost all black or almost all Latino, the top 10 percent of students in those high school classes diversify UT-Austin without formal consideration of race.

Fisher's argument was that past Supreme Court decisions have allowed colleges and universities to consider race and ethnicity only if diversity could not be achieved in race-neutral ways, so the University of Texas had no legal need to consider race. The university in turn said that the percent plan provided it with only a limited level of diversity and that it had the right to take additional measures to assure a greater level of diversity.  Most major college associations backed the University of Texas, as did many civil rights organizations. Asian-American groups split on the case.

To oversimplify, the Texas case is about the extent to which public colleges and universities may consider race and ethnicity in admissions, while the Michigan case is about the extent to which voters can bar such consideration.

Many legal observers have assumed that the Supreme Court would rule on the Texas case before announcing whether it would take the Michigan appeal. Another complication is the challenge the Supreme Court is currently considering to California's Proposition 8, which barred gay marriage in the state. Some of the legal issues in that case -- concerning referendums that deny rights to some people -- could relate to some of the issues raised in the challenge to Michigan's Proposition 2.

The Supreme Court will hear the Michigan case in its term starting in October, while a ruling in the Texas case could come at any time.

Justice Elena Kagan will not participate in deciding either of the affirmative action cases, presumably because of her role as U.S. solicitor general prior to joining the Supreme Court. Of the eight remaining justices, only three are considered generally reliable supporters of affirmative action, and the others -- to varying degrees -- have all appeared skeptical of the consideration of race by colleges and universities.

Had the Supreme Court declined to hear the case, Proposition 2 would have been gone and Michigan's colleges and universities would have been free to resume the consideration of race and ethnicity in admissions. decisions. The inability to do so had the greatest impact at the University of Michigan, but was also felt -- especially at professional schools -- at other universities in the state.

Even though the consideration of the case means that Proposition 2 might now stand, By Any Means Necessary issued a statement praising Monday's development. Shanta Driver, the national chair of BAMN, and a lawyer for the organization, said: "We now have the chance to strike down Michigan’s Proposal 2, California’s Proposition 209 and the other five anti-affirmative action laws that have excluded tens of thousands of black, Latino and other minority students from universities across the country."

But the XIV Foundation (named for the Constitution's 14th Amendment), which campaigns on behalf of measures such as Proposition 2, also praised Monday's news. A statement said: "The Michigan Civil Rights Initiative was backed by 58 percent of the Michigan electorate and simply states that public institutions cannot grant preferential treatment to any group or individual on the basis of race. The Sixth Circuit Court of Appeals overturned the will of the people last November....  We believe the US Supreme Court is poised to overturn the Sixth Circuit’s decision."

Rod Smolla, president of Furman University and author of The Constitution Goes to College: Five Constitutional Ideas That Have Shaped the American University (NYU Press), said via e-mail that he was not surprised that the Supreme Court agreed to consider the appeal. He noted that while the Supreme Court in 2003 ruled that the Constitution "allows" colleges to consider race and ethnicity, that decision did not require such consideration. He also noted that the Sixth Circuit was "deeply divided" on the case.

"Bearing in mind that under the 'rule of four' it only takes four Supreme Court justices to agree to take a case, it does not surprise me at all that four justices would vote to review the Sixth Circuit ruling," Smolla said. "Whatever the outcome of Fisher may be, and whatever the ultimate constitutionality of affirmative action 'on the merits' may prove to be, I suspect a number of justices were troubled by what they perceived as undue interference by a federal court into the sovereignty of a state’s electorate to make such key policy decisions as they see fit — particularly when the affirmative action policies at issue have never been deemed constitutionally required."