WASHINGTON — For the second time this year the House voted to dismantle the military’s "don’t ask, don’t tell" policy, giving the Senate a final shot in the waning days of this Congress at changing a law requiring thousands of uniformed gays to hide their sexual identity.

The strong 250-175 House vote Wednesday propels the issue to the Senate, where supporters of repeal say they have the votes but perhaps not the time to get the bill to the floor. It could be the last chance for some time to end the 1993 law that forbids recruiters from asking about sexual orientation and troops from acknowledging that they are gay.

Democratic leaders in the Senate say they are committed to bringing the bill to the floor before Congress adjourns for the year. But they are challenged by opposition from some Republicans and a daunting agenda that includes finishing work on legislation to fund the government and ratifying a nuclear arms treaty with Russia.

No time has been set for a Senate vote on repealing "don’t ask, don’t tell." Failure to overturn the policy this year could relegate the issue to the back burner next year when Republicans, who are far less supportive of allowing openly gay individuals to serve in the military, take over the House and gain strength in the Senate.

President Barack Obama, in a statement Wednesday night, said he applauded the House vote. In reiterating his support for ending the ban, he pointed to backing for repeal from the defense secretary and the chairman of the Joint Chiefs of Staff.

"Moving forward with the repeal is not only the right thing to do, it will also give our military the clarity and certainty it deserves," Obama said. "We must ensure that Americans who are willing to risk their lives for their country are treated fairly and equally by their country."

Pentagon press secretary Geoff Morrell said in a statement after the House vote that Defense Secretary Robert Gates encourages the Senate to lift the ban and thus enable the Defense Department "to carefully and responsibly manage a change in this policy instead of risking an abrupt change resulting from a decision in the courts."

Last May the House voted 234-194 in favor of repeal legislation as part of a larger defense bill. The measure has stalled twice in the Senate, where Republicans have objected to taking up the defense bill laded with contentious issues, including "don’t ask, don’t tell."

"Now is the time for us to act," House Speaker Nancy Pelosi said Wednesday, and "close the door on a fundamental unfairness in our nation."

Gaveling the end of the vote was Rep. Barney Frank, D-Mass., one of the House’s few openly gay members. Frank, in his floor speech, said it was "bigoted nonsense" that "the presence of someone like me will so destabilize our brave young men and women that they will be unable to do their duty."

"This vote," said Rep. Patrick Murphy, D-Pa., the Iraq war veteran who sponsored the bill, "is about whether we’re going to continue telling people willing to die for our freedoms that they need to lie in order to do so."

Many Republicans, led by Sen. John McCain of Arizona, argue that it would be a mistake for the military to undergo a major cultural change while the nation is fighting two wars.

Implementation of any new policy should begin "when our singular focus is no longer on combat operations or preparing units for combat," said Rep. Howard "Buck" McKeon of California, top Republican on the Armed Services Committee.

The issue also has split the military. Gates and other senior military leaders support lifting the restrictions on gay service, pointing to a recent Pentagon study showing that most people in uniform don’t object to serving with gays. But the head of the Marine Corps, Commandant Gen. James Amos, repeated his opposition this week, saying that lifting the ban during wartime could cost lives.

"I don’t want to lose any Marines to the distraction," Amos said.

The White House, in a statement in support of repeal, stressed that the change would go into effect only after the president, the secretary of defense and the chairman of the Joint Chiefs of Staff certify that implementation is consistent with military readiness, recruiting and retention and unit cohesion.

Joe Solmonese, the president of the gay rights group Human Rights Campaign, said Wednesday’s vote means the House has confirmed for the second time what military leaders, most troops and the American public have been saying, that "the only thing that matters on the battlefield is the ability to do the job."

"It is up to the Senate to consign this failed and discriminatory law to the dustbin of history," Solmonese said.

The House, in introducing the stand-alone bill, sought to avoid the complications of combining it with a general defense bill. Sens. Susan Collins, R-Maine, and Joe Lieberman, I-Conn., also promoted a stand-alone bill in the Senate. Supporters say they have the 60 votes for passage if they can get it to the Senate floor.

"It is now the Senate’s turn to take the final step toward overturning this discriminatory policy," Collins and Lieberman said in a statement. "We are out of excuses."

A major hurdle has been a Republican pledge to block all legislation until the Senate completes work on tax cut and government funding. The Senate on Wednesday passed the compromise on extending tax cuts worked out by the White House and Republicans.

More than 13,500 service members have been dismissed under the 1993 law.

The Obama administration, while supporting the repeal, is appealing the ruling of a California federal judge that the ban on gays serving openly in the military is unconstitutional. The administration says Congress should overturn the policy. But gay rights groups say they will shift their focus back to the courts if Congress fails to act.