There's a lot going on in the Senate re: our failed occupation of Iraq. One of the major questions is: How much power does Congress really have to quash this escalation and/or pull our troops out? This is an ongoing Constitutional issue between Congress and the Executive that hasn't really been fully resolved. There are a lot of arguments, but it's telling to note that many Republicans have shifted their arguments dramatically from when the Executive was a Democrat. Once again, Greenwald does the digging for us
When Bill Clinton was President, most of the country's leading Republicans did not seem to have any problem at all with Congressional "interference" in the President's decisions to deploy troops (really to maintain troop deployments, since President Bush 41 first deployed in Somalia). There wasn't any talk back then (at least from them) about the burden of "535 Commanders-in-Chief" or "Congressional incursions" into the President's constitutional warmaking authority. They debated restrictions that ought to be legislatively imposed on President Clinton's military deployments and then imposed them.
And Sen. McCain in particular made arguments in favor of Congressionally-mandated withdraw that are patently applicable to Iraq today. And he specifically argued with regard to forcible troop withdrawal that "responsibilities for that lie with the Congress of the United States." The Constitution hasn't changed since 1993, so I wonder what has prompted such a fundamental shift in Republican views on the proper role of Congressional war powers.