Supporters of a bill that would allow gays to serve openly in the military worked on Wednesday to marshal the political support needed to end the 17-year-old ban known as "don't ask, don't tell," but the outcome was in doubt.
Landmark votes in the House and the Senate Armed Services Committee were expected to come as early as Thursday.
"This one will go down to the wire, and it won't be over until the vote," said Fred Sainz, a spokesman for Human Rights Campaign.
A breakthrough occurred in the Senate committee Wednesday when Sen. Ben Nelson, a conservative Nebraska Democrat, announced he would swing behind the measure. His decision came after a provision was included that would let the military decide when and how to implement the change in personnel policy.
"In a military which values honesty and integrity, this policy encourages deceit," Nelson said Wednesday.
Nelson's announcement was soon followed by Sen. Robert Byrd, D-W.V., giving the panel the 15 votes needed to pass the measure.
The bill would still face scrutiny by the full Senate, where 60 votes are usually needed to overcome Republican objections, and the House, where Democratic leaders were still surveying party members on Wednesday to gauge support.
But an endorsement by the Senate committee would be a crucial first step. The measure's chances were enhanced by a move to tuck it into a broader defense bill that authorizes billions of dollars in spending on U.S. troops. The bill typically includes popular provisions like a pay raise for the military.
"We are increasingly confident about the (bill) and that this could very well be a historic week in the United States Congress," said Marshall Wittmann, a spokesman for Sen. Joe Lieberman, a Connecticut independent, who is co-sponsoring the legislation.
In the House, Rep. Patrick Murphy, D-Pa., was expected to introduce the legislation as an amendment to the defense authorization bill.
While Murphy said he had enough votes to pass it, some lawmakers — including Democratic Rep. Gene Taylor of Mississippi — threatened to pull their support from the entire defense bill if it did.
Taylor has been a staunch supporter of the annual defense bill for years. But spokesman Ethan Rabin said Wednesday that he feels strongly enough to vote against the massive spending bill if the measure were included.
The legislation was a compromise between the White House and a small group of lawmakers — including Lieberman and Armed Services Committee Chairman Carl Levin, D-Mich. — who fear that efforts to lift the ban would be thwarted if Republicans take control of either the House or the Senate after elections in November.
Nelson said a caveat calling for the military to decide the particulars of implementing the policy was key to his support because it "removes politics from the process" and ensures repeal is "consistent with military readiness and effectiveness."
Defense Secretary Robert Gates has said he supports repeal but would prefer that Congress wait to vote until he can talk to the troops and chart a path forward. A study ordered by Gates is due on Dec. 1.
"With Congress having indicated that is not possible, the secretary can accept the language in the proposed amendment," said Pentagon press secretary Geoff Morrell.
The service chiefs urged the panel not to vote until the Pentagon could interview military personnel.
"The value of surveying the thoughts of Marines and their families is that it signals to my Marines that their opinions matter," Marine Commandant James Conway wrote in a letter to Sen. John McCain of Arizona, the panel's top Republican.
McCain and other lawmakers, including some Democrats, took a similar stand this week and cast doubt on whether the measure would pass. At least one Republican — Sen. Susan Collins of Maine — has said she will support the measure.
Adm. Mike Mullen, the nation's top uniformed officer and chairman of the Joint Chiefs of Staff, told graduating Air Force Academy cadets on Wednesday that they need to support a changing military.
Mullen didn't speak directly about the "don't ask, don't tell" policy. But the chairman, who has said that the policy unfairly forces troops to lie, said service members should question convention.
"Few things are more important to an organization than people who have the moral courage to question the direction in which the organization is headed and then the strength of character to support whatever final decisions are made," Mullen said.
(This version CORRECTS description of Lieberman by omitting reference to 'liberal lawmakers'.)
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