Liberal House Democrats are urging action on legislation aimed at repealing the federal gay marriage ban after last week’s district court ruling that key portions of the 1996 law are unconstitutional. But even pro-gay-rights Members say now is not the time to take up the explosive issue.

Proponents of gay marriage are hailing Thursday’s ruling by a district judge in Boston that the federal Defense of Marriage Act, which defines marriage as a legal union between one man and one woman, violates the Constitution on two counts: It interferes with the right of a state to define marriage, and it violates equal protection principles in the Due Process Clause of the Fifth Amendment.

Rep. Jerrold Nadler (D-N.Y.), who has 112 co-sponsors on his DOMA repeal bill, said the court ruling shows that his legislation is “more relevant today than ever,” and Congress needs to move now.

“I urge the administration and the Congress to work actively to repeal DOMA, in its entirety, and to abandon all efforts to defend that unconstitutional and immoral law,” he said.

But Nadler’s bill has yet to gain traction, largely because it lacks the support of two key allies: Speaker Nancy Pelosi (Calif.) and Rep. Barney Frank (Mass.). Both Democrats said DOMA lacks the votes and instead have advocated that Democrats move on other aspects of the gay rights agenda that are more likely to pass, such as a “don’t ask, don’t tell” repeal and the Employment Non-Discrimination Act, which targets workplace discrimination based on sexual orientation.

“DOMA was never in the mix for this year, and it is highly unlikely that there are the votes for repeal,” a House Democratic leadership aide said. “The agreed-upon priorities for this Congress were hate crimes, DADT repeal and ENDA. Two of these priorities have passed the House — one is enacted — and ENDA remains a priority for this year.”

Another senior Democratic aide said the public wants to see Congress focused on jobs and that Democratic leaders will “limit other issues … that can distract from that message” in the lead-up to November elections.

Despite not signaling interest in taking on the issue in 2010, Pelosi praised the court decision as a major step forward for 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.”

Even co-sponsors on Nadler’s bill acknowledged that Congress is not where the gay marriage debate is likely to play out.

“The right of same-sex couples to marry with the same protections, benefits and obligations as straight couples may, ultimately, be decided by the Supreme Court,” said Rep. Tammy Baldwin (D-Wis.), who along with Frank is one of three openly gay Members.

Still, Baldwin said the ruling “absolutely” has implications for the Hill because it will “help persuade and ultimately change minds” among lawmakers and the public about supporting gay marriage rights.

And while Nadler’s bill may never come to a vote, it is “hugely important because it provides an educational tool … and shows that almost a quarter of the Congress is of the mind that this law is discriminatory and needs to be repealed,” she said.

The relative silence from Members after the ruling was an indicator of just how much Democrats want to keep the issue at an arm’s length for now. Other than a handful of statements from liberal lawmakers, House Democrats kept mum on the matter. Likewise, Democratic Senators who opposed DOMA in 1996 have had little to say on the ruling.

Sen. Arlen Specter (D-Pa.), who last October declared “the time has come” to repeal DOMA in a Huffington Post opinion piece, was “out of reach” Friday and unable to comment, according to his office.

A White House aide declined to weigh in on the ruling and cited the Justice Department’s duty to defend existing statutes. But the aide noted that Justice’s brief on the ruling recognizes President Barack Obama’s position on the issue: He opposes the law.

Some Republicans accused Justice of soft-pedaling its defense of DOMA because of Obama’s stated opposition.

House Judiciary ranking member Lamar Smith (R-Texas) criticized the agency for its “half-hearted defense” and said the president’s personal views should “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.” During her confirmation hearings over the past two weeks, Supreme Court nominee Elena Kagan dodged questions about her position on the constitutionality of the law given the likelihood that the matter will come before the high court. But she said she did not think the Justice Department was holding back in its defense of DOMA.

“I do believe that the Department of Justice is vigorously defending DOMA in that case and in other cases,” Kagan said during a June 30 hearing.