All 15 sitting Senate Democrats who voted for the Defense of Marriage Act (DOMA) now oppose the law.

DOMA, the 1996 law which forbids the federal government from recognizing the legal marriages of gay and lesbian couples, is in national headlines as the Supreme Court prepares for next week's oral arguments in a case challenging its constitutionality.

Patty Murray of Washington state is among those senators who have had a change of heart.

“My state voted, and I voted with them, to allow marriages between gay and lesbian couples,” Murray told NPR. “I'm very proud of my state.”

Ohio Senator Rob Portman earlier this month became the first Republican senator to buck the GOP's official position on gay marriage. And while Portman may now oppose DOMA as a matter of principal, he continues to toe the party line in the respect that he believes “change should come about through the democratic process in the states.”

“An expansive court ruling would run the risk of deepening divisions rather than resolving them,” Portman wrote in an op-ed.

Still, Portman is not among the 10 Republican senators who voted for DOMA and urged the Supreme Court to uphold the law in an amicus brief.

“Look, both of us believe that we should not discriminate against anybody,” said Utah Senator Orrin Hatch, who organized the brief. “But where we do part is that I believe … in the traditional definition of marriage that has existed for, some estimate, 6,000 years.”