Senate Homeland Security Chairman Joe Lieberman (ID-Conn.) said Thursday that at least 60 Members will vote in favor of repealing the military’s “don’t ask, don’t tell” policy during the lame-duck session.

Lieberman, who has led the effort to repeal the policy banning openly gay service members, said GOP Sens. Susan Collins (Maine) and Dick Lugar (Ind.) plan to join Democrats to bring up the defense authorization bill that includes language to repeal DADT. Collins has been a supporter for months, but Lugar’s endorsement gives Democrats fresh hope of clearing the 60-vote threshold to overcome a GOP-led filibuster of the defense measure.

“Based on the statements by Sens. Collins and Lugar and others privately, I am confident we have more than 60 votes prepared to take up the defense authorization bill with the repeal of ‘don’t ask, don’t tell’ if only there will be a guarantee of a fair and open amendment process,” Lieberman said at a press conference Thursday.

Finding time on the calendar to take up the issue will be a challenge, however. Majority Leader Harry Reid (D-Nev.) has a packed calendar following the Thanksgiving break, including consideration of the DREAM Act, a continuing resolution to keep the government funded, an extension of unemployment benefits and the extension of some or all of the Bush tax cuts. Lieberman said Thursday that Members are preparing to stay in session until Dec. 17.

“We’ve been told we’d be here at least three weeks, that’s a lot of time,” he said, recognizing the hefty workload that remains. “It’s just a question of how hard we’re willing to work to get these things done. They’re all important.”

Republicans, including Collins, blasted Reid in September for limiting debate on the defense bill and at that time blocked Democrats from bringing up the measure for consideration.

Sen. John McCain (R-Ariz.), ranking member on the Armed Services Committee, has been in talks with Chairman Carl Levin (D-Mich.) to strip the DADT amendment from the defense bill to build GOP support for the measure. But Reid pledged Wednesday to push the defense bill with the repeal language in it.

“I’ve had discussions; I’ve had no success,” Lieberman said of his own negotiations with McCain.

Lieberman made his comments at a press conference with a dozen other Senators and gay rights activists in a continued attempt to push the Senate to repeal DADT. The House voted in favor of repeal in May, and both President Barack Obama and Defense Secretary Robert Gates have called on the Senate to do the same during the lame-duck session.

“If we don’t get this job done this year, I think it could be years before we have another opportunity,” warned Sen. Mark Udall (D-Colo.).

The Senate will adjourn Friday for the Thanksgiving recess and return Nov. 29 for the last work stretch of the year. The Pentagon is expected to release a report reviewing the DADT policy on Dec. 1. The Armed Services Committee is expected to hold hearings on the report, and the defense bill could hit the floor by the week of Dec. 6.