Senate Democrats celebrated the advancement of legislation to repeal the military’s “don’t ask, don’t tell” policy Saturday but mourned the end of an immigration bill known as the DREAM Act, another top priority that liberals hoped to advance in their waning days of Congressional dominance this year.

The Senate voted 55-41 against a procedural motion to consider the DREAM Act, which creates a path to citizenship for students and members of the military. After that vote went down, six Republicans joined all Democrats in a 63-33 procedural vote to advance legislation to repeal DADT. That legislation is poised for final approval Saturday afternoon.

“This is one of those moments in our history when we stepped up and squared our policies with the values this nation was founded upon,” Majority Leader Harry Reid (D-Nev.) said in a statement. “I applaud those Republicans who have joined us to repeal this policy, and hope that even more will join us on the right side of history when we complete our work, and end ‘Don’t Ask, Don’t Tell.’”

Saturday’s floor vote marked the third time the Senate tried to advance the repeal legislation, which passed in the House on Wednesday. GOP Sens. Susan Collins and Olympia Snowe of Maine, Lisa Murkowski (Alaska), Scott Brown (Mass.) Mark Kirk (Ill.) and George Voinvoich (Ohio) voted in favor of the procedural motion. Sen. Joe Manchin (W.Va.), the only Democrat who came out against repeal, did not vote.

President Barack Obama vowed to repeal DADT during his presidential campaign and made the case strongly for repeal in his first address to a joint session of Congress in 2009. Obama mentioned the need for “fixing our broken immigration system” in his State of the Union address this year, although the line drew disappointment from advocates who maintained his plea was not forceful enough. After the Senate’s failed vote on Saturday to advance the DREAM Act, Obama issued a statement calling for action.

“It is disappointing that common sense did not prevail today. But my administration will not give up on the DREAM Act, or on the important business of fixing our broken immigration system,” he said. “The American people deserve a serious debate on immigration, and it’s time to take the polarizing rhetoric off our national stage.”

Conference Vice Chairman Charles Schumer (D-N.Y.), who also leads the Judiciary subcommittee on immigration, announced at a news conference Saturday that “immigration reform is hardly dead.” But the outlook for immigration reform next year, when Democrats will hold just a 53-vote majority, is grim. Just three Republicans voted to advance the DREAM Act, and five Democrats voted against. Republicans in favor were Sens. Bob Bennett (Utah), Murkowski and Sen. Dick Lugar (Ind.), who is up for re-election in 2012 and may face a primary challenge from the right thanks in part to this vote. The defecting Democrats were Sens. Kay Hagan (N.C.), Mark Pryor (Ark.) and Max Baucus and Jon Tester of Montana. Tester, who also faces re-election in 2012, is one of Republicans’ top targets as they attempt to take control of the Senate.

Republicans blasted Democrats for pushing votes on a pair of liberal priorities in the waning days of the legislative year, when Members still must approve a continuing resolution to keep the government funded and potentially adopt the new Strategic Arms Reduction Treaty. Republicans have warned in recent days that action on DREAM or DADT would severely threaten the passage of START. Sen. John McCain (R-Ariz.), the ranking member on the Armed Services Committee who has led the revolt against the DADT repeal, took it one step further Saturday by saying Reid’s action on the floor would poison next year’s environment in the Senate.

McCain called it a “bizarre world” in which Reid has been pushing issues on Democrats’ political agenda. Given that, he asked, “Do you somehow think that beginning next Jan. 5 we will all love one another and ‘Kumbaya’? I don’t think so.”

The DADT bill, pushed by Sen. Joe Lieberman (I-Conn.), would repeal a 1993 law enacted under President Bill Clinton. The Pentagon this month released findings of its survey of active-duty members and their families showing repeal would not harm troop morale or readiness.

“Plenty of people had already planned the funeral for this legislation,” said Fred Sainz, vice president of the Human Rights Campaign. “Today, we pulled out a victory from what was almost certain defeat just a few days ago.”