By Jonathan Stempel
WASHINGTON (Reuters) - The Supreme Court will in late March hear oral arguments in a pair of cases challenging laws that define marriage as a union of a man and a woman.
On March 26, the court will review a California ban on gay marriage, which voters narrowly approved in 2008. That case could give the court a chance to accept or reject a constitutional right to same-sex marriage, or issue a narrower ruling affecting only the nation's most populous state.
The next day the court will review a New York court ruling striking down a centerpiece of the Defense of Marriage Act, a federal law that denies married same-sex couples a variety of federal benefits that heterosexual couples receive.
The scheduling was announced in a calendar released by the court on Monday. In May, President Barack Obama said he believed same-sex couples deserve the right to marry, and the government is no longer defending the federal benefits law.
Both cases are the most anticipated in the court's current term and are among several cases that could allow the nine justices to better define what constitutes equality.
In October, the court heard arguments challenging the use of affirmative action in admissions at the University of Texas at Austin. Next month, it will hear a challenge to a central provision in the Voting Rights Act of 1965.
Decisions in these cases are expected by the end of June.
In the California case, Hollingsworth v. Perry, the 9th U.S. Circuit Court of Appeals had last February voided the same-sex marriage ban but ruled narrowly, saying the state could not take away a right to same-sex marriage after previously allowing it.
That case was brought by two lawyers, Theodore Olson and David Boies, who were on opposite sides in the 2000 case Bush v. Gore, which decided the 2000 U.S. presidential election.
The New York case, U.S. v. Windsor, challenged Section 3 of the Defense of Marriage Act, which defines marriage as between only a man and a woman for the purpose of benefits such as Social Security survivor payments and the right to file joint federal tax returns.
In October, the 2nd U.S. Circuit Court of Appeals in New York struck down Section 3, in a decision by Chief Judge and Republican appointee Dennis Jacobs, joining a May 2012 ruling by a federal appeals court in Boston.
Thirty-one of the 50 U.S. states have constitutional amendments banning same-sex marriage. Nine states and Washington, D.C. have legalized it, including three on Election Day in November.
While state laws still largely disfavor same-sex marriage, public support has been rising.
Last month, the Pew Research Center said 48 percent of Americans say they favor allowing gays and lesbians to marry legally, and 43 percent oppose it. In 2008, 39 percent supported same-sex marriages and 51 percent opposed it, Pew said.
The cases are Hollingsworth v. Perry, U.S. Supreme Court, No. 12-144; and U.S. v. Windsor, U.S. Supreme Court, No. 12-307.
(Editing by Cynthia Osterman)