Washington (AFP) – The U.S. Supreme Court considered whether state referendums can ban race and sex as factors in university admissions.

In 2006, Michigan voted on a measure to disallow so-called affirmative action in college admissions.

The high court heard arguments Tuesday on whether the ban is constitutional, considering the U.S. constitution’s equal protection guarantees.

Outside, on the Supreme Court steps, some 200 mostly minority protesters gathered to defend affirmative action.

Inside the court Chief Justice John Roberts, a conservative appointed by former U.S. president George W. Bush, said the point of the constitution’s Equal Protection Clause was specifically designed “to take race off the table.”

Conservative Justice Antonin Scalia weighed in similarly.

“We’ve held that the 14th Amendment protects all races,” he said. “You say now that we have to proceed as though its purpose is not to protect whites, only to protect minorities?”

Of the nine justices, progressive Sonia Sotomayor, who is of Puerto Rican descent and was appointed by U.S. President Barack Obama, defended affirmative action the most vehemently.

“Affirmative action favors diversity as opposed to discrimination,” she said.

“You can’t take away a tool of diversity, simply because you change plans,” the justice said.

Justice Elena Kagan, a progressive and former solicitor general, has recused herself from the case due to a conflict of interest linked to her previous professional functions.

This means the remaining eight justices — three progressives and five conservatives — will decide on the matter, although their ruling is not expected before next year.

Michigan Attorney General Bill Schuette asked the justices to uphold “Proposition 2,” adopted in Michigan in 2006 but struck down by an appeals court.

The proposition prohibited Michigan’s public universities, colleges, and school districts from “discriminating against, or granting preferential treatment for any individual or group on the basis of race, sex, color, ethnicity, or national origin.”

But a coalition of groups backing affirmative action along with 17 former students argued the reform violates the U.S. Constitution — specifically its provision on equal rights.

The Michigan case comes on the heels of a high-court decision just over three months ago concerning affirmative action at the University of Texas.

In that case, the justices elected not to rule on the constitutionality of using race and ethnicity in admission, instructing a lower court to take another look at the matter.

The decision left unchanged the principle of affirmative action, an enduring legacy of the 1960s civil rights movement originally meant to give African-Americans a leg up in applying for jobs and education to counter decades of racism.

Brian Soucek, acting professor at the University of California, Davis School of Law, said repercussions from the court’s upcoming decision will be felt well beyond Michigan’s universities.

Apart from Michigan, seven other states — California, Arizona Florida, Nebraska, New Hampshire, Oklahoma and Washington state — have banned affirmative action.