Not really a surprise. After becoming the 60th vote on financial reform, he needs a gesture to “prove” to Massachusetts conservatives that he’s still one of them. But even so: According to CNN’s poll today, 78 percent of Americans support repealing DADT, along with nearly six in 10 Republicans. (That’s in line with other polls, incidentally. An ABC survey taken in February found 75 percent support overall.) Even among blue-state GOPers, his vote here won’t do much for him.

Brown says that while he is keeping “an open mind” on future efforts, he believes any vote for repeal should be put off until the Pentagon has time to formulate a plan for implementing any new policy.

“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 said in a statement provided to the Globe…

“For some time now, I have been seeking the opinions and recommendations of service chiefs, commanders in the field, and, most importantly, our junior soldiers, sailors, airmen, and Marines,” he said in the statement. “I believe we have a responsibility to the men and women of our armed forces to be thorough in our consideration of this issue and take their opinions seriously.”…

Criticism from some gay rights groups was swift and unsparing. “The notion that the senator from Massachusetts — the first state in the nation to have marriage equality and one of the first states to have an anti-discrimination law — would oppose ending discrimination against gays military personnel is reprehensible,” said Arline Isaacson, co-chair of the Massachusetts Gay and Lesbian Political Caucus.

In Massachusetts, 77 percent support repeal, along with 62 percent of Brown voters. Susan Collins, who’s not in quite the same amount of electoral jeopardy as he is, says she’ll support repeal — but the Dems aren’t out of the woods yet. Lindsey Graham’s also voting no for the same reason Brown is (i.e. we should wait until the Pentagon review is finished) and Jim Webb(!) is reportedly leaning that way too. These are all members of the Armed Services Committee, of course, and without a majority in favor of repeal there, there’s no way to attach a repeal amendment to the defense appropriations bill and bring it to the floor for a final vote. There are 16 Democrats on the committee and 12 Republicans, so with Collins and Webb swapping votes, there’s still a two-vote margin in favor of attachment. HuffPo notes, though, that both Nelsons — Bill and Ben — are shaky. If they end up voting with Brown, the Committee’s deadlocked at 14, which likely means the repeal effort is stalled until the Pentagon comes back with its review in December. Exit question: If, as is expected, Gates and Mullen generate a report insisting that they can implement a policy of service by openly gay members, how will the new, more conservative Congress next year vote? Remember — 78 percent of the public’s in favor.

Update: Another interesting poll: For the first time ever, a majority of Americans say gay relationships are morally acceptable.