Seeking to stir opposition to a proposed constitutional ban on gay marriage, the House’s only three openly-gay Members are attempting to gain unlikely allies by appealing to a pair of GOP favorites: states’ rights and Vice President Dick Cheney.

In a “Dear Colleague” letter sent to Members on Friday, Reps. Barney Frank (D-Mass.), Tammy Baldwin (D-Wis.) and Jim Kolbe (R-Ariz.) cited statements made by Cheney during the 2000 vice presidential debate, in which he said marriage should be regulated by individual states rather than the federal government.

“Recently Members have been asked to cosponsor a Constitutional amendment on the subject of marriage. Many of its supporters have sought to portray it as a question of whether or not same-sex marriages should be allowed,” the letter states. “In fact, what is most radical about this amendment is not that it defines marriage, but that it takes away from each of the fifty states the right to decide this question and give it for the first time in our two hundred year history to the federal government.”

The legislation, introduced by Rep. Marilyn Musgrave (R-Colo.) in May and now awaiting action by the House Judiciary subcommittee on the Constitution, would define marriage to include only a man and a woman.

“Marriage and family are the most important institutions in existence. Unfortunately they have come under attack,” Musgrave said in a statement in May. “The traditional values Americans hold are being traded in for counterfeit marital unions. It is important to secure this institution and protect it from distortion.”

The current bill, which has 39 co-sponsors in the House, has garnered attention in recent weeks as the Supreme Court quashed a Texas anti-sodomy law and the Canadian government gave its approval to gay marriages.

It also received a notable boost when Senate Majority Leader Bill Frist (R-Tenn.) voiced his support for such an amendment during a June 29 appearance on ABC’s “This Week.”

“A lot of Republicans were not expecting to deal with this, don’t think the federal government ought to force the issue, [and] weren’t looking to get into it,” Frank said. “There’s a lot of people who said, ‘This is a tough issue, let’s stay out of it.’ Then Frist comes up, and I think somewhat irresponsibly and unnecessarily, endorses it and that made a lot of Republicans uncomfortable.

“What I’m offering the Republicans … is a way that’s consistent with their conservative principles not to support this amendment,” Frank added.

Although Frank hopes to garner support on both sides of the aisle, a Kolbe spokeswoman said the states’ rights argument does not prohibit looking at the issue from other perspectives.

“Congressman Frank drafted this letter and approached Congressman Kolbe to sign on. As a strong states’ rights advocate, Congressman Kolbe felt that this is a very powerful argument to make,” the spokeswoman said. “This does not mean that there are not other arguments to make. Bottom line, the Congressman is opposed to a constitutional amendment on marriage.”

Frank said he has not spoken recently to Cheney, whose daughter Mary is gay, about the issue, but said he plans to raise it in the future.

A Cheney spokeswoman did not return a call seeking comment. During the 2000 debate, Cheney said, “I try to be open-minded about it as much as I can, and tolerant of those relationships … I also wrestle with the extent to which there ought to be legal sanction of those relationships.”

A Constitutional amendment must be approved by two-thirds of the House and Senate and then ratified by three-fourths of the states.

“This is the best way to deal with it, and the question here is not whether or not you’re for gay marriage, but whether or not you think the people in a particular state ought to be able to make their own decisions,” Frank said.