AS CONGRESS PREPARES to vote on a supplemental defense appropriations bill that includes timelines for the withdrawal of U.S. forces, the lines in the debate over Iraq strategy have become ever starker. The administration and other defenders of the present strategy insist that it be given the chance to succeed. Opponents, including the Democratic leadership in Congress, insist that it is time to begin winding down America's involvement in Iraq. Some of those opponents no doubt seek only to defeat the administration or appease their own constituents, but many honestly believe that rapid withdrawal is the best course of action. Their arguments generally come down to two points: success is already beyond our reach, and setting timelines is the best way to force the Iraqis to take the difficult steps required to achieve a political settlement to this conflict. There is an inherent contradiction in these positions that war opponents must work out before acting on them, but, more importantly, neither proposition is true.

The notion that the war is already lost, articulated most recently by Senate Majority Leader Harry Reid, rests on the belief that Iraq has descended into a spiral of sectarian violence from which it cannot recover. In this view, the traditional hatred between Sunni and Shia became ungovernable after al Qaeda's destruction of the Golden Mosque of Samarra in February 2006. The continuing violence in Iraq, which is still often referred to as "sectarian violence," is cited as evidence of this death-spiral. Many who hold this view believe

Such beliefs are incompatible with the notion that American-imposed deadlines or timetables would force the Iraqi government to make necessary compromises. If the war is lost, it is because the Maliki government is unwilling to make those compromises and, presumably, is willing to engage in mass killing, if necessary, to achieve its aims. Alternatively, Iraq's government might be too weak to control the violence, in which case the issue is not the pressure they face to make the right decisions, but their inability to do so. Either way, it is hard to see how using the threat of withdrawing American forces would help the situation.

So the real alternative buried in the idea behind deadlines is that the war is not, in fact, lost. The Iraqi government could make the right decisions if it chose and could enforce them on its people, given suitable incentives. Another implicit assumption in this view is that Sunnis might accept the limitation of their power in Iraq and enter the political process if the Shiite government reached out to them properly.

Congress must decide which view it wishes to embrace. If the war is truly lost, then timelines serve no useful purpose in Iraq except to delay the departure of American troops. To argue that deadlines are a constructive force in Iraqi politics is to argue that success is still possible.