has a thought similar to mine, but puts a different spin on it:

Administration officials claim that this time things are different. The Maliki government, and the Shiite leadership more generally, understand that they must crack down on militias and compromise with the Sunnis. Why? In the words of one senior U.S. official—under instructions to stay anonymous—because Shiite political leaders understand they no longer have “unquestioning American support anymore, especially from Capitol Hill.” This suggests that the administration finally understands that Bush’s blank-check policy for the Iraqi government has proved totally counterproductive. The one action that might be forcing the Iraqi leadership to make some compromises has been the threat that Congress would force a withdrawal of American support. One month ago, the White House was criticizing Congress as being borderline treasonous for suggesting such a thing. Today its strategy in Iraq rests on the fruits of that assertiveness.