The U.S. Supreme Court term that begins Monday promises to be one of the most important for civil rights in decades, with the potential for blockbuster decisions on issues from race in classrooms and the voting booth to legal recognition for same-sex marriage.

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Less than a decade after ruling that the nation's colleges and universities can consider the race of student applicants to achieve more racially diverse campuses, a practice now widely used by the nation's selective schools, the court has agreed to take a fresh look.

The new challenge comes from Abigail Fisher, a white student denied admission to the University of Texas at Austin. The school admits the top 10 percent of academic performers from all Texas high schools, then considers the race of applicants as one factor in admitting the remainder of an incoming freshman class.

Evan Vucci / AP People who waited in line overnight to hear the Supreme Court on a landmark case on health care hold their belongings as they make their way into the court in Washington, Thursday, June 28, 2012.

Fisher did not finish in the top 10 percent at her high school and claims that the consideration of race in reviewing applications cost her a spot at the university.

"There were people in my class with lower grades, who weren't in all the activities I was in, who were accepted into UT. And the only difference between us was the color of our skin," she said.

The university, backed by civil rights groups, contends that while the top 10 percent plan achieves some campus diversity, many of its classes would have only a few, if any, black and Hispanic students without additional considerations of race.

Making it harder to achieve the diversity colleges need, argues Gregory Garre, a Washington, D.C. lawyer representing the University of Texas, "would jeopardize the nation's paramount interest in educating its future leaders in an environment that best prepares them for the society and workforce they will encounter."

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The Supreme Court that will hear the case Oct. 10 is different from the one that upheld a race-conscious admissions program at the University of Michigan law school in 2003.

"Sandra Day O'Connor was on the court then, and she's been replaced by Samuel Alito, who has much less tolerance for affirmative action," says Tom Goldstein, a Washington, D.C. lawyer who specializes in Supreme Court cases.

O'Connor, who wrote the decision in the Michigan case, retired from the court in 2006.

As a result, says Pamela Harris, a former Obama administration official in the Justice Department, "I don't think anyone thinks affirmative action is long for this world."

Justice Elena Kagan, considered one of the court's liberals, will sit this one out. She was the Obama administration's solicitor general when the Justice Department became involved in the case in the lower courts.

The Supreme Court will take up another racially charged issue this term if, as seems likely, it agrees to consider efforts to scale back the landmark Voting Rights Act.

Passed by Congress in 1965 and renewed four times since then, most recently in 2006, a key provision requires states with a history of discrimination at the polls to get federal permission before making any changes to election procedures -- from redrawing congressional district boundaries to changing the locations of polling places.

Three years ago, the Supreme Court brushed off a challenge to that requirement but strongly suggested that several justices had doubts about its constitutionality, given recent electoral reforms.

"Things have changed in the South," the court said in 2009. "Blatantly discriminatory evasions of federal decrees are rare."

Pending cases ask the court to strike down the pre-clearance requirement entirely or throw out the list of areas, consisting of nine entire states, and of 12 cities and 57 counties elsewhere, that must get permission to modify their election procedures.

The current map, says Bert Rein, a Washington, D.C. lawyer representing Shelby County, Ala., includes some localities that have made substantial reforms while missing other parts of the country that have failed to root out discrimination at the polls.

As a result, Rein says, the system is unfair. "Florida has been forced into pre-clearance litigation to prove that reducing early voting from 14 days to 8 is not discriminatory, when states such as Connecticut, Rhode Island and Pennsylvania have no early voting at all."

But Debo Adegbile of the NAACP Legal Defense and Education Fund says the current map is a close enough fit to cover the areas of greatest concern.

"Congress is not a surgeon with a scalpel when it acts to legislate across the 50 states. But it can reasonably attack discrimination where it finds it," he says.

The court is almost certain to take up a host of challenges to the federal Defense of Marriage Act (DOMA) signed into law by President Bill Clinton in 1996.

It defines marriage, for the purposes of federal law, as "only a legal union between one man and one woman as husband and wife." As a result, same-sex couples who get married in the states where such marriages are legal are accorded state and local benefits but miss out on more than 1,100 federal ones.

After at first defending the law, the Obama administration notified federal courts early last year that it concluded the law was unconstitutional. House Republicans then took up the law's defense.

A Supreme Court ruling striking down DOMA as discriminatory would not force states to permit same-sex marriage. But it would require the federal government to recognize those marriages where they are legal.

The court could address the issue of same-sex marriage more directly if it takes up the legal challenge to California's Proposition 8, which banned gay marriage in the state.

Legal experts differ on whether the court is prepared to go that far, rather than deciding the DOMA issue now and coming back to the constitutionality of gay marriage in a later term.

"We're not at the point where the Supreme Court will require the state of Mississippi to allow same-sex marriage," says Louis Michael Seidman of the Georgetown University Law Center.

Among other questions the justices will confront:

- Must police get a search warrant before taking a blood sample from a suspected drunk driver?

- How far can police go in using drug-sniffing dogs outside someone's house?

- Can a 1789 law, the Alien Tort Statute, be used to bring lawsuits in US courts for violations of international law that occur in other countries?

- And, in an issue of growing interest to U.S. businesses, should more limits be placed on the ability to bring class-action lawsuits?