Capitol Hill insiders say D.C.’s same-sex marriage bill, which is undergoing its required congressional review, should not be adversely affected by Tuesday’s election of Massachusetts Republican Scott Brown to a U.S. Senate seat.

“It had nothing to do with same-sex marriage — nothing at all,” said U.S. Rep. Barney Frank (D-Mass.), who is gay.

Frank and other Capitol Hill observers have said the D.C. marriage bill, which must clear a 30 legislative day review in Congress, is moving ahead as expected, with Democratic leaders in the House and Senate committed to blocking any attempt to overturn the bill during the review period.

“I think we’re in pretty good shape and, obviously, we’re going to watch it,” Frank said. “But I don’t think you’re going to see any stirring up in that.”

Gay Republican activist Bob Kabel, chair of the D.C. Republican Party and a same-sex marriage supporter, said Wednesday that he agrees with Frank’s assessment relating to the congressional review.

“I’m not sure how Scott Brown’s election can make a difference at all,” Kabel said. “He’s more or less a social conservative. But he ran on economic issues. He ran clearly against the health care bill and the way the Democrats handled — or mishandled — the health care debate.”

Kabel noted that Virginia Gov. Robert McDonnell, a staunch social conservative, and New Jersey Gov. Christopher Christie, both Republicans, won their respective races in November also by stressing economic and good-government issues rather than social issues, such as gay marriage.

Kabel and others monitoring the GOP gubernatorial victories in Virginia and New Jersey, plus the Brown victory in Massachusetts this week, noted these victories should not be viewed as a voter rejection of LGBT rights.

“The people I would be concerned about in Congress on the D.C. marriage bill would be the blue dog Democrats,” said Kabel, referring to the moderate-to-conservative Democrats in the House from GOP-leaning districts.

Capitol Hill insiders have long said that LGBT rights legislation could be blocked if enough blue dog Democrats join Republicans to oppose pro-LGBT bills. But many of the same insiders note that on the D.C. marriage bill, LGBT supportive Democrats have a clear advantage because it’s always easier to block bills than to pass them.

On the D.C. same-sex marriage bill, opponents must secure enough votes to affirmatively pass a disapproval resolution during the congressional review period and President Obama must sign it in order for it to pass.

“That’s just not going to happen,” a House Democratic aide said. “What’s more likely is opponents will try to attach a rider to D.C.’s fiscal year 2011 appropriations bill” to kill the marriage bill, which would have become law by that time.

Most observers expect the D.C. marriage bill to clear its congressional review in early to mid March. The city’s appropriations bill is expected to come up in Congress in the summer or early fall.

The House Democratic aide and other Hill observers said they were uncertain about the impact of Brown’s victory in Massachusetts on the ability of same-sex marriage opponents to successfully attach an amendment to the D.C. budget bill killing the marriage law. Up until now, most political observers believed the Democratic-controlled House and Senate would block any effort to kill the D.C. marriage law through an appropriations amendment.

“I think anti-marriage members of Congress may be emboldened by Scott Brown’s victory,” said Michael Crawford, co-chair of the same-sex marriage advocacy group D.C. for Marriage.

“But I think they are going to have a real challenge trying to prevent marriages from being performed here in D.C.,” he said. “We are going to be working very, very hard to convince members of Congress to do nothing on the issue because that’s exactly what we want them to do. And we’re going to continue to push them to allow the laws of the District to be decided by the elected representatives of the District.”

Michael Mitchell, executive director of National Stonewall Democrats, an LGBT partisan group, said the organization is scheduled to launch a national campaign next week in support of D.C.’s same-sex marriage bill.

He said the campaign will urge LGBT Democrats and their supporters across the country to call on their members of Congress to allow the D.C. law to go into effect without congressional interference.

“Last night’s election in Massachusetts was never going to be a make-or-break moment for our community’s agenda,” said Joe Solmonese, president of the Human Rights Campaign. “The simple truth we have known all along is that the Democratic majority does not equal a pro-LGBT majority.”

Solmonese joined Mitchell in calling on congressional Democratic leaders not to back away from their campaign promises to support LGBT rights bills and oppose ballot measures seeking to ban same-sex marriage.