Senator Susan Collins, a Maine Republican, said Tuesday she supports repeal of “Don't Ask, Don't Tell,” the AP reported.

Collins is considered a critical vote in the Senate Armed Services Committee that is expected to vote Thursday on attaching an amendment to the defense budget that would repeal the Clinton-era law that prohibits gay troops from disclosing their sexual orientation.

The committee includes 12 Republicans, most of whom are leaning against voting for the measure, including ranking Republican Arizona Senator John McCain. McCain has become the face of opposition to repeal in the Senate.

Massachusetts Republican Scott Brown, who blew into office on a right-wing platform, has already said he'll vote against the measure.

After the White House and Pentagon united in urging Congress to postpone repeal until it completes an implementation study, support from conservative Democrats on the panel softened. But on Tuesday, President Barrack Obama and Defense Secretary Robert Gates backed a compromise measure that would delay implementation of repeal until after the study is concluded and Obama, Gates and Admiral Mike Mullen, the chairman of the Joint Chiefs of Staff, agree on the policy changes.