politics of iraq
I think Juan Cole has some very honest and sharp points on the subject, here.
The Democrats even with trying to legislate Baker-Hamilton, will not be able to overturn a veto in the House of Representatives. What will happen I bet is what Petraeus said will happen. One brigade or so down a month until by mid-08, and then more or less 100-130,000 troops will still be in Iraq as Bush leaves office.
By that reckoning, the best the Democrats in a sense can hope for is that Petraeus does some good in the meantime. Because Republicans are going to likely lose the White House and the next Democratic president will have to make the hard decisions Bush was never willing to (admit loss of peace not war). I think that President, likely Clinton, will only last one term, and the Democrats are dumbly taking the fall guy pill yet again, like in Vietnam. In that war, it was less clear cut, given that Johnson (a Dem) escalated the war and Nixon (a Rep.) was the one that started the pullback. In this war it was a war of choice, sold by a Republican administration, that many a Democrat stupidly caved in on.
Obama has a new, fairly detailed plan for getting out of Iraq. Has some good things on political pressure, UN mediation, Iraq in the context of the Middle East, and the one that will get most play domestically, his call for basically all combat troops (minus protection forces and residual al-Qaeda force, plus troops in Kurdistan and Kuwait) out by 08. It's not going to happen. It might help him politically, might not. But again I think it's largely irrelevant.
As Thomas Ricks says, if you liked the first phases of this war, you'll love the next one.