WASHINGTON » Advocates of a bill that would overturn the military’s "don’t ask, don’t tell" policy say their fight for repeal this year is far from over despite failing to pass the Senate with only days left in the lame-duck session.

Senate Republicans blocked the legislation Thursday, which would have lifted the military’s 17-year-old ban on openly gay troops. The measure was added to a broader defense policy bill and had passed the House last spring.

It failed in a 57-40 test vote, falling three votes short of the 60 needed to advance.

GOP senators mostly united in defeating the measure on procedural grounds, insisting that the Senate vote on tax cuts first. Maine Sen. Susan Collins was the only Republican to vote yes.

Collins and Sen. Joe Lieberman (I-Conn.) are now pushing stand-alone legislation they insist could be considered before the Senate’s target adjournment next week. Its prospects are uncertain, although Reid indicated he was open to bringing it up before the holiday break.

If passed, the bill still would require House approval, with time growing short.

"We’ve got at least 60 votes, so we’re going to keep up the fight," said Lieberman. "But we’re not kidding ourselves, this is not going to be easy."

Hawaii Sen. Daniel Akaka is co-sponsoring the measure.

In a statement yesterday, Akaka noted the recent Pentagon study showing a large majority of troops are prepared to serve with openly gay service members. The Senate Armed Services Committee member said congressional action that results in orderly implementation of a new policy is preferable to a judicial order.

House Speaker Nancy Pelosi promised to do what she could to get repeal legislation on the president’s desk by the end of the year.

"An army of allies stands ready in the House to pass a stand-alone repeal of the discriminatory policy once the Senate acts," she said in a statement Thursday.

The White House appeared to embrace that approach yesterday. "The president remains committed to seeing this repeal done before Congress leaves town this year," said press secretary Robert Gibbs. "And I think there could be legislative vehicles that start in the House as a stand-alone that can withstand procedural hurdles and put the Senate on the record on an up-or-down vote that would repeal ‘don’t ask, don’t tell.’"