Senator Scott Brown, a Massachusetts Republican, said Tuesday he'll vote against repeal of “Don't Ask, Don't Tell,” the Boston Globe reported.

Brown 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.

“I am keeping an open mind, but I do not support moving ahead until I am able to finish my review, the Pentagon completes its study, and we can be assured that a new policy can be implemented without jeopardizing the mission of our military,” Brown told the Globe.

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.

Maine Republican Susan Collins appears to be the only Republican maverick on the panel; she said Tuesday she'll vote in favor of repeal.

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.