Updated: July 8, 7:33 p.m.

A U.S. district court judge in Boston ruled Thursday that the federal ban on gay marriage is unconstitutional, a decision that brings a jolt to an issue otherwise dead on Capitol Hill.

Judge Joseph Tauro ruled in favor of gay couples’ rights in two separate challenges to the 1996 Defense of Marriage Act, which defines marriage as a legal union between one man and one woman. Tauro issued one ruling on the grounds that DOMA interferes with the right of a state to define marriage. In the other case, he found that the law violates the equal protection principles embodied in the Due Process Clause of the Fifth Amendment.

Gay and Lesbian Advocates and Defenders, the gay rights organization that filed one of the cases, posted the decision on its website Thursday. One of the plaintiffs, Dean Hara, had been in a committed same-sex relationship with former Rep. Gerry Studds (D-Mass.). Studds served in Congress from 1973 to 1997, and he died in 2006.

A spokesman for Speaker Nancy Pelosi (D-Calif.) praised the decision as a step forward in the name of equality.

“The Speaker strongly supports today’s ruling that the Defense of Marriage Act violates the constitutional guarantee of equal protection,” Pelosi spokesman Drew Hammill said. “We must continue to work against division and distraction in our country, and work toward the day when all American families are treated equally.”

But the issue has gone nowhere in this Congress and left House Democrats divided on how to proceed. Rep. Jerrold Nadler (D-N.Y.) filed DOMA repeal legislation in September and picked up 112 co-sponsors, but two key signatories were noticeably missing: Pelosi and Rep. Barney Frank (D-Mass.), one of three openly gay Members.

Frank declined to endorse the bill because he said he did not think it was achievable in the near term. Instead, he took on the stance adopted by Pelosi, which has been to move first on aspects of the gay rights agenda that are more likely to pass, such as securing full domestic benefits for federal employees and protections against workplace discrimination based on sexual orientation.

But Rep. Mike Quigley (D-Ill.), one of the co-sponsors of Nadler’s bill, said Thursday’s court ruling reaffirms his commitment to pushing for a repeal.

“I agree that the Defense of Marriage Act is an unconstitutional intrusion into state and individual rights, and I will continue to push for its repeal,” he said. “These decisions affirm Lincoln’s statement at Gettysburg that this nation is always moving towards freedom and equality for all.”

House Judiciary ranking member Lamar Smith (R-Texas) blasted the Justice Department for its “half-hearted defense” in the case, which he chalked up to President Barack Obama’s stated opposition to DOMA.

“The president’s personal views have nothing to do with the defense of a law passed by Congress. The Justice Department has a responsibility to appeal this decision and defend the laws passed by Congress on behalf of the American people,” Smith said. Thursday’s court ruling “defies the will of the American people and directly contradicts the spirit of democracy that is government by the people and for the people,” he added.

Melanie Starkey contributed to this story.