Nancy Pelosi Attends Supreme Court Arguments, Predicts DOMA Will Be Struck Down Andrew Harrer/Bloomberg/Getty Images After attending oral arguments at the Supreme Court today to debate the constitutionality of the Defense of Marriage Act, House Minority Leader Nancy Pelosi, one of the most outspoken advocates in Congress for marriage equality, said she believes that when the justices announce their ruling in a couple of months, they will strike down the controversial law commonly known as DOMA. "On the basis of what I heard, the questions of the justices, the response of the participants, I'm very optimistic that DOMA will be struck down," said Pelosi, D-Calif. Just being in the room ... this [issue] is as big as our country, as big as our Constitution, as big as our being a beacon of equal protection to the world. While Pelosi and many of her Democratic colleagues have openly embraced gay marriage over the years, House Republicans have resisted the Obama administration's unwillingness to enforce DOMA, which defines marriage as a union between one man and one woman and was signed into law by President Bill Clinton in 1996. House Speaker John Boehner, R-Ohio, has persistently insisted that as long as the Obama administration refuses to enforce DOMA, the Bipartisan Legal Advisory Group [BLAG], which is comprised of three Republicans and two Democrats, will defend the law. "A law's constitutionality is determined by the courts - not by the Department of Justice," Boehner spokesman Michael Steel wrote in a statement today. As long as the Obama administration refuses to exercise its responsibility, we will. Today, Pelosi said she believes Congress and the nation have evolved since DOMA was first signed into law and she predicted that opposition to gay marriage is "not a model for the future." "We're at a different place, and it's a generational change as well," Pelosi said. Times can blind, and whatever the public mood was on this subject at the time, it also created some ignorance on the subject. And that ignorance is fading now. "Make America more American by ending discrimination by overturning the ill-conceived DOMA," she added. SHOWS: Nightline What Would You Do World News