Although I am not a lawyer who deals with these sorts of constitutional issues so I could be completely wrong, looking at the Iraq War Resolution and the War Powers Resolution (as well as a Supreme Court case from wayyyy back in the day) makes be think that Congress has the power to order Bush to withdraw troops right now.
Though Democrats and Republicans alike act like Bush is Dictator-in-Chief, that simply doesn't seem to be the case.
The resolution granting the President the authority to invade Iraq if diplomatic efforts failed (haahaha) allowed the use of force for two reasons.
- To protect the US from the threat posed by that madman Saddam
- To enforce UN Resolutions
Neither of those things is what our forces are being used for today. So it would appear that the President is using US forces for actions that fall outside of the bounds set by Congress.
The Supreme Court in Little v. Barreme held that the President may not use the military beyond the scope set by Congress.
The War Powers Resolution allows Congress to order the President to remove troops where forces are:"engaged in hostilities outside the territory of the United States, its possessions and territories without a declaration of war or specific statutory authorization, such forces shall be removed by the President if the Congress so directs by concurrent resolution."
I believe Bush, by seeking to quell a civil war rather than protect the US from the threat posed by Saddam or enforce UN resolutions, is operating without specific statutory authority and Congress, if they really meant that they don't agree with either the war or escalating the war, could order him to withdraw US forces any time they choose.
I'd be happy and grateful if people could/would add to the legal analysis.