Gay service members who reveal their sexual orientations during congressional testimony would be immune from forced discharges under a bill introduced earlier this month, as lawmakers prepare to consider repealing the ban on gays serving openly in the U.S. military.

The legislation’s author, U.S. Rep. Alcee Hastings, D-Fla., said the bill is needed to ensure that Congress has reliable and relevant witnesses at its disposal if the House holds hearings next year on the “Don’t Ask, Don’t Tell” policy.

The bill also would protect from retaliatory personnel actions any members of the military who testify for or against lifting the 16-year ban.

“How can there be anything more important than a gay member of the service having the right to testify before the Armed Services Committee of the Congress that he is under the aegis of,” Hastings told The Associated Press. “But if they come and testify, that testimony could be used against them under ‘Don’t Ask, Don’t Tell.’ In my judgment, it’s just a question of fairness.”

Hastings so far has secured 27 Democratic co-sponsors for his “Honest and Open Testimony Act.” But the measure also has met surprising opposition from leading gay veterans groups and other Democrats who have been at the forefront of the movement to repeal the policy.

Alexander Nichols, executive director of Servicemembers United, an advocacy group for gay Iraq and Afghanistan war veterans, said the legislation is good in theory but on a practical level would not protect gay service members who out themselves to Congress from becoming pariahs within their units.

“This proposal is, of course, well-intentioned and the idea behind it is certainly noble, but I believe it is a bit naive in its conceit and doesn’t reflect a thoughtfulness on what this would mean for gay and lesbian service members,” Nichols said. He thinks it is better for gay veterans to share their experiences than to put active duty service members at risk.

Aaron Belkin, director of the Palm Center, a think tank devoted to gays in the military at the University of California, Santa Barbara, said that if the bill passes, it would be the first dent in “Don’t Ask, Don’t Tell” since the policy prohibiting service members from acknowledging they are gay was adopted in 1993. As such, it represents an important step toward full repeal, Belkin said.

“I don’t think there is any down side,” he said. “Politically, it is a very poignant thing to put a gay person on the stand because that is shining a spotlight on the lie that structures the whole policy. The move, in and of itself, before they even say anything, is powerful ammunition.”

Since “Don’t Ask, Don’t Tell” took effect, nearly 13,000 troops have been dismissed because it became known they were gay. President Barack Obama said he favors lifting the ban but has asked for more time to persuade opponents in the Pentagon.

U.S. Rep. Patrick Murphy, D-Pa., the first Iraq war veteran elected to Congress, has been shepherding a “Don’t Ask, Don’t Tell” repeal bill toward hearings in the House, but he was not among the lawmakers who signed onto Hastings’ measure.