Washington (CNN) -- The Supreme Court's conservative majority appeared to look favorably on Michigan's voter-approved law that bans use of racial criteria in college admissions.
An hour of oral arguments Tuesday afternoon raised anew thorny, unresolved questions over race and remedies.
The justices are being asked to decide the constitutionality of a 2006 referendum that prohibits race- and sex-based discrimination or preferential treatment in public university admission decisions. That ban was written into the state's constitution.
The high court appeared to divide along ideological lines over whether the law has the effect of restructuring the political process to make it harder for minority groups to enact policies benefiting them, in possible violation of the 14th Amendment.
"It seems the goal posts keep changing every few years for minorities," said Justice Sonia Sotomayor, over efforts to blunt or eliminate affirmative action.
"You could say that the whole point of something like the Equal Protection Clause is to take race off the table," said Chief Justice John Roberts. "Is it unreasonable for the state to say, race is a lightning rod?"
The high court just 16 weeks ago affirmed the use of race at the University of Texas, but made it harder for institutions to justify such policies to achieve diversity.
In that dispute, a white student said the college's existing affirmative action policy violated her "equal protection" rights, while civil rights supporters of such programs claim Michigan's ban also has the same effect.
A federal appeals court last year concluded the affirmative action ban, which Michigan voters passed in a 2006 referendum, violated the U.S. Constitution's equal protection guarantees.
It was the latest step in a legal and political battle over whether state colleges can use race and gender as a factor in choosing which students to admit.
The law was passed seven years ago with support of 58% of voters. It was added to the state's constitution, and bars publicly funded colleges from granting "preferential treatment to any individual or group on the basis of race, sex, color, ethnicity or national origin."
That prompted a series of lawsuits and appeals from a coalition of civil rights groups and University of Michigan faculty and students, who counter the law actually burdens state residents, denying them the opportunity to persuade state and college officials that classroom and workplace diversity remains a necessary government role.
Michigan voters approved the ban after the U.S. Supreme Court ruled in 2003 that while state universities could use race as a factor in choosing which students to admit, they could not make race the determining factor in deciding whether applicants are accepted.
Outside the court Tuesday, several hundred supporters of the By Any Means Necessary coalition favoring affirmative action rallied outside the court.
"They say Jim Crow. We say hell no," said BAMN attorney Shanta Driver, who addressed the cheering crowd through a megaphone. "We won't accept the new Jim Crow." Many of the marchers were bused in from the University of Michigan.
The intense arguments in the courtroom were equally passionate.
John Bursch, the state's solicitor general, cited competing statistics that minority enrollment at the university has not gone down since the measure was passed. Civil rights groups dispute those figures and say other states have seen fewer African-American and Hispanic students attending highly competitive schools, especially in graduate level fields like law, medicine, and science.
"It's a forward-looking action, not a backward-looking action, to remedy past discrimination," Bursch said of the voter-approved Proposal 2. "There are other things that the University of Michigan could be doing to achieve diversity in race-neutral ways."
Sotomayor appeared skeptical. "Busing could be viewed, and was viewed, to benefit only one group. It was a preference for blacks to get into better schools. That's the way the case was pitched, that was its justification, to integrate the society," she said. "Affirmative action has the same gain. We've said that in (the Texas case decided in June), it should be to diversify the population, so it favors diversity as opposed to desegregation."
But the toughest questions came from the conservative bloc. Justice Anthony Kennedy and Samuel Alito repeatedly questioned whether judicial respect for the political process would give voters the ultimate power to block race preferences, or whether should such admission criteria should be made by the school itself.
"Why is the faculty administration, a faculty decision, any less outcome determinative than what the voters would say?" asked Kennedy
Justice Antonin Scalia said the Equal Protection Clause can be interpreted broadly. "We've held that the 14th Amendment protects all races," he told BAMN's Driver, making her case. "You say now that we have to proceed as though its purpose is not to protect whites, only to protect minorities?"
Driver: Equal protection is "a measure in which the question of discrimination is determined not just by those who have privilege in this society, but by those minorities that are oppressed, be they religious or racial-- they need protection from a more privileged majority."
Scalia: "And unless that exists, the 14th Amendment is not violated-- is that right? So if you have a banding together of various minority groups who discriminate against whites, that's okay? Do you have any case of ours that propounds that view of the 14th Amendment, that it protects only minorities? Any case?"
"No case of yours," admitted Driver.
Outside the court, the law's supporters were optimistic the court would find in their favor.
Prop 2 "embodies the fundamental premise of what America is all about: equal opportunity under the law," said Bill Schuette, Michigan's attorney general. "Entrance to our great universities must be based upon merit."
The referendum effort was led by Jennifer Gratz, who was at the center of the decade-old high court case.
As a white student, she was put on the waiting list for undergraduate admission to the state's largest university. She eventually attended another school, and became the lead plaintiff in a subsequent discrimination lawsuit.
After the Supreme Court's 2003 decision, she began a public campaign to end racial preferences in admissions.
"This will be an important day in the fight for true equality," said Gratz, who is now CEO of the XIV Foundation, which advocates for "equal treatment." "How the court rules in this case will have national importance, determining whether or not citizens have the right to choose equality over discrimination."
The Michigan ban also prohibits the state from considering race and gender in public hiring and public contracting decisions. But the current high court case deals only with the college admissions portion.
Efforts over decades to create a diverse classroom have been controversial.
The Brown v. Board of Education high court ruling in 1954 ended segregation of public schools, but sparked nationwide protests and disobedience by states that initially refused to integrate.
In the 1978 Bakke case, the justices ruled universities have a compelling state interest in promoting diversity, and that allows for the use of affirmative action. That issue involved a discrimination claim by a white man denied admission to law school.
The referendum issue has been around at least since 1996, when California voters endorsed Proposition 209, which bans use of race, sex, or ethnic background by state agencies in areas of education, and government hiring and contracts. Six other states now have similar laws, and others may follow suit, depending on how the high court rules.
The high court under Chief Justice John Roberts has made the issue a key part of its docket in recent years, and it could serve as a major legacy of the current conservative majority.
The debate in recent years is whether and when affirmative action programs -- while constitutionally permissible now -- would eventually have to be phased out as the goal of obtaining diversity is met.
Now-retired Justice Sandra Day O'Connor -- who wrote the key ruling a decade ago in the initial Michigan cases -- said, "The court expects that 25 years from now, the use of racial preferences will no longer be necessary to further the interest approved today."
The justices are now being asked once again to decide whether Michigan's current policy in this case meets that legal and social test.
Justice Elena Kagan will not hear this petition, leaving the possibility of a 4-4 high court tie and no important precedent being established.
The case is Schuette v. Coalition to Defend Affirmative Action, Integration & Immigrant Rights, and Fight for Equality by Any Means Necessary (12-682). A written ruling could come as late as June.