WASHINGTON — For the second time, Ken Mehlman — the one-time head of the Republican National Committee — is gathering notable Republicans and libertarians around the country to support a brief at the Supreme Court that will urge the justices to take marriage equality nationwide.

"There is a need for more Americans to choose to participate in the institution of marriage," states the brief, a copy of which was reviewed by BuzzFeed News. "Yet these bans, by denying each member of an entire class of American citizens the right to marry the person he or she loves, discourage those important family values."

In an interview with BuzzFeed News, Mehlman emphasized that the brief — to be filed next week in the marriage cases pending before the justices — is consistent with the Republican Party's aims.

"What we hope it will do is it will make the case from a conservative, from a libertarian perspective," Mehlman said, "that marriage equality is consistent with promoting freedom and family values — and, as we've seen in the states where there is civil marriage today — can be done in a way that in no way impacts or harms religious liberty and, in fact, explicitly protects religious liberty in many of these states."

Among the new names joining Mehlman's effort on the brief are several notable former public officials and prominent operatives in the Republican Party, including former lawmakers Bob Inglis, Steve LaTourette, and Rick Lazio.

Inglis has come full circle on the issue — noted in news stories at the time for his aggressive questioning of Democratic witnesses who opposed the Defense of Marriage Act when the House of Representatives was considering the bill in 1996.

"The signers of this brief, myself included, are people who very much disagree with judicial activism," Mehlman said. "We believe that the court standing up for the right of loving couples to marry one another is consistent with our constitutional order and necessary that same was that overturning bans on free speech are necessary or overturning bans on the Second Amendment are necessary to protect liberty."

Among other new signatories this time around are the spokespeople for the past two Republican presidential candidates, McCain 2008 spokesperson Tucker Bounds and Romney 2012 spokesperson Andrea Saul. Ron Kaufman, a prominent Romney 2012 adviser, and Zac Moffatt, Romney 2012's digital director, also signed on.

Former George W. Bush administration officials Jon Berrier, who was the communications and political affairs coordinator for Vice President Cheney, and T. Vance McMahan, who was the U.S. ambassador to the United Nations Social and Economic Council, have signed the Mehlman brief, as has Erin Sheley, a law professor who served as the deputy director of the Federalist Society's faculty division from 2008-2010.

Since Mehlman came out in 2010, he has been supportive of marriage equality — an effort that followed his time at the helm of the Republican National Committee when the party backed the passage of many of the amendments he is now working to overturn.

One of his first big public efforts to support marriage equality was hosting a major fundraising event for the American Foundation for Equal Rights in 2010 in support of the group's case against California's Proposition 8 amendment. When that case got to the Supreme Court, Mehlman coordinated an amici curiae, or friends of the court, brief to encourage the court to see that the issue had support from a broad swath of conservatives and moderate Republicans.

Now, with the issue before the justices again, Mehlman is back with a new effort, authored by lawyers at the Wilmer Cutler Pickering Hale & Dorr — including Reginald Brown and Seth Waxman — and Polsinelli law firms.

With just a few days of circulating the brief for signatures, the brief has increased the number of signatories — which was 131 in 2013 — by more than 50. And, they expect more before the brief is filed.

Mehlman says that, as more places have gained marriage equality, people see that "America is more free, that important values like fidelity and responsibility are more promoted, by allowing all Americans to marry the person that they love.

"So, people have now seen this happen in most states in the United States and the concerns that some people had about what the impact would be have not only not occurred, but the opposite's occurred: Families are stronger, communities are stronger, and freedom is stronger."

In the brief, the lawyers echo points made in the Prop 8 case amici brief, as well as a similar amici brief filed in 2014 at the 10th Circuit Court of Appeals in the marriage cases out of Utah and Oklahoma.

"The marriage bans challenged here, like the act at issue in Windsor, target gay and lesbian couples and their families for injurious governmental treatment," the brief states, referring to the 2013 Supreme Court decision striking down the Defense of Marriage Act's federal ban on recognition of same-sex couples' marriages in United States v. Windsor. "The bans are accordingly inconsistent with amici's understanding of the properly limited role of government."

The brief goes on to argue that "equal access to civil marriage" is required "because there is no legitimate, fact-based justification for government to exclude same-sex couples in committed relationships" from the right to marry. "Such bans impede family formation, harm children, and discourage fidelity, responsibility, and stability," the brief states.

In responding to the 6th Circuit Court of Appeals' decision upholding the states' bans, the Mehlman brief criticizes the opinion by Judge Jeffrey Sutton deferring to the democratic process.

"It is ... not a violation of principles of judicial restraint for this Court to strike down laws that infringe 'fundamental rights necessary to our system of ordered liberty,'" the brief states. "It is instead a key protection of limited, constitutionally constrained government."

If, as Mehlman and his co-signers argue, the court ends bans on same-sex couples' marriages across the country this June, he said he doesn't expect a result different than elsewhere when marriage equality came to other states. "I think people in all states are fundamentally fair-minded," he said, reiterating that people in those remaining states would see that families, communities, and freedom are stronger with marriage equality in place.

As for what's next for LGBT efforts after such a ruling, Mehlman said the marriage movement is part of "a larger recognition" by Americans.

"I think and hope and believe that the same fundamental decency and fairness that is causing more Americans — a majority today — to say 'you ought to be able to marry the person you love,' will also say, to those people, 'you ought to be judged at work by the quality of your efforts,' and support … legislation that makes sure people are judged on a fair basis at work," he said.