The U.S. military is bound by an international Status of Forces Agreement (SOFA) to withdraw all combat troops from Iraq by the end of 2011.
In Iraq, people took to the streets to celebrate the occasion, and with good reason. For years now (if not from the very start of the war), a majority of Iraqis have viewed American soldiers as occupiers barring their country's path towards self-determination.
Yes, the phased withdrawal of American troops will create a power vacuum; it will detract from the hard-earned security gains made from Bush's largely successful 2007 troop surge; and the prospect of resumed sectarian violence between various Shiite and Sunni armed groups vying for power with the government remains very real.
But the war was wrong to begin with. Drawing it to a close is the one of the best foreign policy decisions the U.S. has made in years.