William Kristol at The Weekly Standard has a good article covering the state they're in now, with the surge showing signs of success.
With the ongoing progress of the surge, and the obvious fact that the vast majority of the troops want to fight and win the war, the "support-the-troops-but-oppose-what-they're-doing" position has become increasingly untenable. How can you say with a straight face that you support the troops while advancing legislation that would undercut their mission and strengthen their enemies?
You can't. So those on the cutting edge of progressive opinion are beginning to give up on even pretending to support the troops. Instead, they now slander the troops.