WASHINGTON — A historic week at the Supreme Court may transform the rights of racial minorities and gays, potentially cutting longstanding voting protections for blacks and Hispanics while allowing a new wave of same-sex marriages.

The justices take the bench today to issue the first of 11 decisions before their nine-month term ends. The court is considering limiting university affirmative action, striking down a core part of the landmark Voting Rights Act, invalidating a federal law that defines marriage as an opposite-sex union, and overturning California's ban on gay weddings.

The result may be a turning point in a debate over equality that has raged since the 14th Amendment was ratified in 1868. While the cases offer paths for the justices to avoid the central constitutional questions, the disputes also give them an opportunity to rewrite the nation's civil rights laws.

"In the court's modern history, I don't think there has ever been one week with so much at stake," said Tom Goldstein, a Supreme Court lawyer whose Scotusblog website tracks the court and is sponsored by Bloomberg Law. "We have four pending cases that may be cited for at least a century."

The court traditionally finishes its term in the final days of June, meaning all four rulings are likely by the week's end.

Even before the court issues its first decisions, it may announce a blockbuster case for its 2013-14 term. At 9:30 a.m. the justices will release a list of new cases, potentially including a showdown over President Obama's recess appointments to the National Labor Relations Board.

The affirmative action dispute is the court's longest- pending case. The delay since the Oct. 10 argument has fueled questions about the maneuvering that may be going on behind the scenes and the impact that may have on the outcome.

UPDATE:

The Supreme Court has sent a Texas case on race-based college admissions back to a lower court for another look

The dispute involves the University of Texas, which admits three-quarters of its freshman class on the basis of high school class rank. Because many Texas high schools are either heavily Hispanic or heavily black, the system ensures a significant minority presence at the state's flagship public university. The issue for the Supreme Court is whether the university may consider race in admitting the rest of its class.

The October argument suggested the court's Republican- appointed majority, including likely swing vote Anthony Kennedy, was poised to strike down the Texas policy without necessarily barring affirmative action at other universities.

U.S. Supreme Court justices take the bench today to issue the first of 11 decisions, which could change civil rights in the U.S. for decades to come

Eight months of wrangling have given the justices time to explore other options, including a more sweeping ruling. They could overrule all or part of the 2003 Supreme Court decision that said universities may consider race in admissions to ensure a "critical mass" of minorities on campus.

The court could also sidestep the affirmative action case in what would be a disappointment to opponents of racial preferences. The justices could conclude that Abigail Fisher, the rejected white applicant challenging the policy, now lacks the legal right to press the case because she has already graduated from a different university.

The court will also rule on the 1965 Voting Rights Act, which opened the polls to millions of Southern blacks. An Alabama county is challenging the provision that requires that all or parts of 15 states get federal "preclearance" before making any change to their voting rules.

As with affirmative action, the conservative majority cast doubt on preclearance during February arguments, questioning whether it was still needed to protect minorities. Those same justices were also skeptical when they scrutinized the law four years ago. The justices later delivered a lesson on the hazards of predicting outcomes based on arguments when they reached a compromise ruling that spared the preclearance requirement.

The two gay-marriage cases are the first the court has ever considered. The justices are reviewing California's Proposition 8, a 2008 ballot initiative that banned same-sex marriage after a state court decision had permitted it for five months. The high court could limit its ruling to California or issue a nationwide decision.

The second case tests the U.S. Defense of Marriage Act, known as DOMA, which denies federal benefits to legally married same-sex couples. Gay marriage is legal in 12 states and the District of Columbia.

Both clashes offer the justices procedural options that would let them avoid ruling on a whether the Constitution requires equal treatment for gay men and lesbians. In the California case, the justices spent much of the March 26 argument debating whether the defenders of Proposition 8 had the legal right to appeal.

The court has a similar option in the DOMA case. The Obama administration's decision to oppose the law, even while continuing to enforce it, has created questions about the jurisdiction of federal appeals courts to review the measure.

A decision throwing out the DOMA challenge on jurisdictional grounds would leave the law in a state of disarray, potentially applying in some parts of the country. It would also be a blow to gay-rights advocates whose hopes were raised after Kennedy voiced skepticism about the law during arguments in March.

The prospect of a jurisdictional ruling on DOMA received renewed attention in recent days after Adam Winkler, a law professor at the University of California at Los Angeles, wrote that he had heard speculation among Washington lawyers about that potential outcome.

A year ago, last-minute speculation about the fate of Obama's health-care law proved correct. Chief Justice John Roberts joined the court's four Democratic appointees in voting to uphold the measure.

A jurisdictional decision on DOMA "would be bad for the law," Winkler said. "It would be bad for the gay-rights movement. It would be bad for the Obama administration."

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