A US judge has struck down a 1996 federal law barring gays and lesbians from receiving federal benefits, the latest in a series of court decisions pushing the issue of same-sex marriage closer to a Supreme Court reckoning.

The ruling by Claudia Wilken of the US District Court for Northern California is the third by district level judges that have declared the 1996 law known as the Defense of Marriage Act, known as DOMA, to be unconstitutional.

Along with a parallel challenge to a California law banning same-sex marriage, the decisions mean the US high court could be hearing arguments about the emotionally charged and politically fraught issue of marriage for gays and lesbians within the next two years.

“It wasn’t a revolutionary decision by any stretch,” says Brian Moulton, legal director for the Human Rights Campaign, a Washington-based gay-rights organization, “but the fact we have yet another judge ruling on DOMA, it’s a constant drum beat at this point, and we’ll see what Supreme Court has to say about it. Sooner rather than later.”

President Obama’s historic announcement that he supports same-sex marriage, and Republican challenger Mitt Romney’s opposition to it, have already stoked the election-year fires on the issue. Earlier this month, voters made North Carolina the 30th state to pass a constitutional amendment prohibiting same-sex marriage. Hawaii’s legislature has also barred same-sex marriage, though there is no amendment there.

DOMA, which was signed into law by President Clinton, defines marriage as a legal union between a man and woman and prevents gays and lesbians who are married under state law from qualifying for more than 1,000 federal benefits, such as Social Security survivor payments or filing joint tax returns.

In her decision Thursday, Judge Wilken agreed with arguments that the law unfairly barred gay and lesbian couples from claiming long-term care benefits in California, violating their rights to equal protection. She cited some of the deliberations Congress had in the run-up to passing DOMA, saying there congressional record showed “evidence of moral condemnation and social disapprobation of same-sex couples.

“The legislative history described above demonstrates that animus toward, and moral rejection of, homosexuality and same-sex relationships are apparent in the congressional record,” she wrote.

She also cited a 1996 US Supreme Court decision on a Colorado anti-gay initiative that found gays and lesbians are protected from "burdensome legislation that is the product of sheer antigay animus and devoid of any legitimate governmental purpose."

That argument is outrageous, says Dale Schowengerdt, legal counsel for the Alliance Defense Fund, which supports DOMA.

"To say that a law that was passed by overwhelmingly by Congress … to say that that’s the product of animus is – I don’t know how to say it – it's unbelievable,” he says. “It’s just unbelievable that a judge would be making that sort of value judgment against the entire government, the Congress, and President Bill Clinton."

"Every civilization throughout history has found that marriage involves a man and a woman, and we're confident that once the Supreme Court has this case, they will find there’s no animus and that the opposite sex was granted in a rational basis," he says.

Mr. Clinton has since said he regretted backing DOMA.

Thursday's ruling will likely be appealed, joining the two other DOMA cases – one from Boston, the other from San Francisco – that are currently being considered by appellate courts.

While those three cases hinge on arguments about the question of equal protection for gays and lesbians, the case involving California’s Proposition 8 turns on the question of due process and whether the Constitution contains a right to marriage for gays and lesbians. A three-judge appeals court has upheld arguments that Prop. 8 is unconstitutional, but opponents have asked a larger appeals panel to rehear the case.

Legal experts expect one or all of those appeals decision to be taken up by the US Supreme Court within the next two years.

Meanwhile, a new poll published Wednesday found that 53 percent of Americans now say gay marriage should be a legal, while 39 percent say it should be illegal, a new high and new low for both those figures, according to the Washington Post-ABC News survey. The survey also found Americans are split nearly evenly on whether same-sex marriage laws should be made by states or by the federal government.

The telephone poll surveyed 1,004 adults from May 17-20 and had a margin of error of 3.5 percentage points.