Now Musgrave is debating congressional veterans, constitutional experts and gay and lesbian activists on the merits of the proposed amendment, which has more than 115 co-sponsors. Evangelical churches invite her to speak about her amendment, and she has been the subject of a clutch of profiles in the national news media.
Her critics have accused Musgrave of hate-mongering and gay-bashing, of being willing to alter the fundamental document of American democracy for the sake of political expediency.
"What I've been struck by more than anything else is her singularly anti-gay position," said Winnie Stachelberg, a lobbyist with Human Rights Campaign, a gay, lesbian and transgender rights lobbying organization. "Her main focus is discrimination against the gay and lesbian community."
After debating Musgrave about the proposed amendment, Rep. Barney Frank (D-Mass.), who is openly gay, said he thought he had taken her measure. "There are some who think that homosexuality is immoral and evil -- I think that's where she's at politically."
Musgrave bridled at his characterization. "I am continually astonished at Barney Frank's arrogance and lack of respect for others," she said in a written response. "Remarks such as these, combined with his extreme views ... show why Mr. Frank isn't taken very seriously within Congress."
The congresswoman's supporters say they admire her willingness to fight for deeply held beliefs.
"She's definitely taking political risk," said Tom McClusky of the conservative Family Research Council, a group that initially pushed to have a ban on civil unions too but has since decided to support the amendment. "For a freshman congresswoman to be so bold -- Democrat or Republican -- that should be admired."
Musgrave became the sponsor of the amendment after she received a visit last spring from Matt Daniels, founder of the nonprofit Marriage Alliance. Daniels had written a proposed constitutional amendment but was having no luck in his effort to find a congressional sponsor.
Musgrave, who had pushed for a Defense of Marriage Act in the Colorado Legislature, seemed the ideal candidate.
"I wanted somebody who was familiar with the issue, who knew that there would be a lot of pressure on them -- especially at that early stage," Daniels said in an interview. "It was clear to me that she was somebody who had counted the cost and would be OK with that, because of her deep personal convictions."
