DEAL IN PLACE FOR DADT REPEAL…. The effort to repeal the “Don’t Ask, Don’t Tell” policy faced a challenge that put success at risk. The White House supported repeal, but was deferring to the Pentagon on timetables and implementation. The Pentagon supported repeal, but wanted to wait until after a review was complete in December. Congressional Democrats supported repeal, but were reluctant to move forward without the administration’s endorsement. Worse, waiting until after the elections was a recipe for almost certain failure.

Yesterday, leading Democratic policymakers worked out the details of a breakthrough deal, and it appears that repeal is finally on track.

President Obama has endorsed a “don’t ask, don’t tell” compromise between lawmakers and the Defense Department, the White House announced Monday, an agreement that may sidestep a key obstacle to repealing the military’s policy banning gay men and lesbians from serving openly in the armed forces.

The compromise was finalized in meetings Monday at the White House and on Capitol Hill. Lawmakers will now, within days, vote on amendments that would repeal the Clinton-era policy, with a provision ensuring that any change would not take effect until after the Pentagon completes a study about its impact on troops. That study is due to Congress by Dec. 1.

In a letter to lawmakers pushing for a legislative repeal, White House budget director Peter Orszag wrote Monday that the administration “supports the proposed amendment.”

Giving the effort an added boost, Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, announced his endorsement of the agreement, as well.

As part of the deal, implementation would be delayed until after the Pentagon review is complete in December, and even then, would take effect after the administration concluded that the new policy will not adversely affect military readiness, recruitment, and retention.

Gay rights groups, which have been aggressive in urging DADT’s repeal, are on board with the agreement. The Human Rights Campaign hailed the deal, and the Servicemembers Legal Defense Network announced that it is “enthusiastically” urging members of Congress to support it.

The only variable at this point happens to be the most important one: it’s still “not clear whether the deal had secured the votes necessary to pass the House and Senate.” Efforts to convince wavering Dems, most notably some Democratic moderates on the Senate Armed Services Committee, are continuing apace. The agreement is in place, but no one should assume that passage is a foregone conclusion.

We’re likely to see votes as early as Thursday. With support from the White House, the Pentagon, the chairman of the Joint Chiefs, and the Democratic leadership in both chambers, I’m cautiously optimistic.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.