WASHINGTON -- The Senate Armed Services Committee voted Thursday to end "don't ask, don't tell," the controversial policy barring openly gay men and lesbians from serving in the military.

The measure, which passed 16-12, includes a provision ensuring that no change would take effect until after the Pentagon completes a study about its impact on troops, due to Congress on Dec. 1.

The House was scheduled to vote by today on an identical measure. Lawmakers there expect it to be approved, and the full Senate would vote on it next month.

The provision, which lawmakers are attaching to a $726 billion defense funding bill, would take effect only if the Defense Department study determines that changing the policy would not affect the military's ability to fight wars or recruit personnel.

The legislation is a compromise between the administration and gay rights activists, who long have opposed "don't ask, don't tell" as effectively allowing one of America's most powerful institutions to discriminate.

Activists pushed President Barack Obama and congressional Democrats on this issue, leading Obama to endorse this approach rather than wait for the Pentagon to finish its study.

Secretary of Defense Robert Gates and Navy Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, have endorsed this approach while emphasizing the importance of the study. Mullen has said he supports repeal, calling it "the right thing to do" in testimony before Congress in February.

Many Republicans on Capitol Hill oppose changing the policy, arguing that Congress should wait until the Pentagon completes its study before acting. The heads of the four uniformed service branches also have said Congress should wait for the completion of the Pentagon study.

Two major veterans service organizations also oppose the Democratic effort.

"We believe changing a major social policy in the middle of two wars would be a mistake and distraction," said American Legion National Commander Clarence Hill.

Duane Miskulin, national commander of AMVETS, said Congress should wait to act until after the Pentagon completes its study of how to implement a repeal. "We can't simply overturn 'don't ask, don't tell' and deal with any unintended consequences after the fact while trying to fight two wars," Miskulin said.

Supporters have said they anticipate that 20 to 30 percent of service members discharged under the ban may re-enlist. Mike Almy, a former Air Force officer who was discharged in 2006, said he's still medically and physically qualified to serve.

"This is all I want to do. I dedicated my whole life to being an officer," said Almy, who has worked as a defense contractor since his discharge and is active with the Servicemembers Legal Defense Network, a group pushing for repeal.

The group reminded members this week that the gay ban remains in place until after the Pentagon completes its study. "Lesbian, gay and bisexual service members remain vulnerable to being discharged on the basis of their sexual orientation," read an e-mail sent to SLDN's 80,000 members.

"While Congress is taking steps to enact a roadmap for full repeal and the implementation of open service, it is not safe to ... serve openly until the process of repeal is complete."