By Ros Krasny
BOSTON (Reuters) - A federal appeals court in Boston heard arguments on Wednesday about the constitutionality of a law that denies federal benefits to married same-sex couples - a case with implications for gay marriage across the United States.
Lawyers for the Bipartisan Legal Advisory Group of the U.S. House of Representatives (BLAG) sought to defend the 1996 law, which the Obama administration essentially abandoned in 2011.
Plaintiffs, including seven married same-sex couples and three widowers, say that the federal Defense of Marriage Act (DOMA), which disqualifies their marriages from equal protections and responsibilities available to other spouses, discriminates against them.
It is the first time an appeals court has considered the constitutionality of DOMA, which defines marriage as a union between a man and a woman, and thus prevents the federal government from recognizing same-sex marriages.
A federal judge in Massachusetts declared a key section of DOMA unconstitutional in 2010. Massachusetts made same sex marriages legal in 2004, the first U.S. state to do so.
On Wednesday, a three-judge panel heard oral arguments in the companion cases of Gill v. Office of Personnel Management and Massachusetts v. Health and Human Services. A ruling on the closely watched cases could take several months.
Mary Bonuato, civil rights project director at Boston-based Gay & Lesbian Advocates and Defenders (GLAD), argued on behalf of the plaintiffs before Massachusetts Chief Judge Sandra Lynch, Judge Michael Boudin and Judge Juan Torruella.
"DOMA's precise point was to create an across the board exclusion of same-sex couples in the U.S. Code," Bonauto told the court.
"The promise of equal protection is that likes are to be treated alike - but DOMA treats married same-sex couples differently from all other married persons, making gay people and our marriages unequal to all others," she added.
Paul Clement, a former solicitor general who last week earned rave reviews for his arguments against the Obama administration's healthcare program before the Supreme Court, represented the congressional group, a five-member panel led by House Speaker John Boehner.
Among other things, Clement was asked whether DOMA was "forcing states to change their laws to comply."
The Department of Justice announced in February 2011 that it considered DOMA unconstitutional and would no longer defend it. DOJ attorney Stuart Delery reiterated that position on Wednesday.
In Gill, filed by GLAD in 2009, the plaintiffs argued that DOMA violates the equal protection provisions of the Fifth Amendment by discriminating against gay and lesbian couples who are married under the laws of the state they live in but denied federal marriage benefits by the government.
In the companion case, Massachusetts Attorney General Martha Coakley claims that Congress overstepped its authority and violated the Tenth Amendment in passing DOMA, because the law undermined states' abilities to recognize marriage equality.
"We think we will be victorious," said Coakley said outside the court. "It's about fairness."
Among the plaintiffs in GLAD's case is Dean Hara, the widower of former U.S. Congressman Gerry Studds, who died in 2006. Studds, the first openly gay member of Congress, and Hara were married one week after same-sex marriages became legal in Massachusetts. Hara is not eligible to receive the pension provided to surviving spouses of former members of Congress.
Kris Mineau, president of the Massachusetts Family Institute, said same-sex marriage, which the group opposes, was a "national states rights issue."
"This would force a radical social agenda on the rest of the 50 states and we believe that is not in keeping with what our federal system is about," Mineau said.
(Editing by Cynthia Osterman)