Nonetheless, there are many, including many in Congress, who think that success in Iraq is compatible with inflexible timelines. It is not; inflexible timelines will lead inevitably to defeat.

The Bush administration, its generals, and external proponents of the current strategy have been clear from the outset: the surge of forces in Iraq is, and was always, intended to be temporary. Its primary aim was to establish security for the people of Iraq (and clearly, it is succeeding in that aim). After security had been brought to a tolerable and stable level, it was expected that the Iraqi government could begin to make significant progress toward political reconciliation at the national level. In the meantime, Coalition forces would continue to work to increase the size of the Iraqi Security Forces, and to improve the quality of those forces. The expectation since the start of the surge has been that as both security and the capabilities of the ISF improved, it would become possible to begin to reduce American forces in Iraq, most likely sometime in 2008. All indicators on the ground now suggest that we are on track to achieving this goal.

The key point is that the reduction of U.S. forces in Iraq, according to this plan, will be driven by changes in the circumstances on the ground. Only when and where the ISF is able to take over maintaining security, will the American forces, accordingly, be able to pull back. In places where the ISF is not yet able to do so, the U.S. forces will remain. The decisions rest with the commanders on the ground who alone can evaluate these conditions.

The American commanders, with whom these decisions reside, are fully cognizant of the strains the deployments are placing on the armed forces (they should know best, after all, since most of them are now serving their second, third, or fourth tours in Iraq or Afghanistan). Drawing on the evidence gathered in the course of their own frequent visits to U.S. and Iraqi units, combined with the intelligence at their disposal, American commanders in Iraq are uniquely qualified to offer an assessment. The only reason they would oppose withdrawing American troops from a given area is that they believe such a withdrawal would harm the mission, lead to in increase in violence and terrorist activity, and place American interests in danger.

Many Americans, and in particular many politicians, are naturally frustrated with the war and want to bring it to an end. Many are calling for the imposition of timelines for the reduction of American combat forces to certain levels, by certain dates. Congressmen and senators have proposed and voted for legislation containing such timelines. But timelines can really only mean one of two things: They can indicate goals from which commanders are free to deviate, depending upon the changing circumstances on the ground. According to this definition, timelines are not fundamentally different from the current strategy, which seeks to reduce the U.S. presence as rapidly as possible without compromising American interests in Iraq and the region.

Alternatively, they can indicate a fixed and inflexible requirement to be followed even if the situation on the ground does not justify them. Applied to the current situation in Iraq, this would translate into a requirement for defeat. In short, if we mandate that U.S. commanders reduce forces in areas they believe cannot sustain their own security, then we are ordering them to accept an increase in violence and terrorist activity in their areas. If we issue such an order for the entire country, we are issuing an order to accept failure country-wide.

Some argue that the U.S. has already failed in Iraq and success is impossible. The solid evidence of improving security and grassroots political movement seems clearly to undermine that argument, but if one sincerely believes that success is no longer possible, then it makes sense to demand a change in strategy. Even then, however, setting arbitrary timelines and force caps is extremely dangerous. If Harry Reid is right and the U.S. has already lost in Iraq, it does not follow that the U.S. can just pull out and let all its interests in the region slide.

Even leading war opponents, who advocate immediate troop reductions, recognize that the U.S. will have to continue to fight al Qaeda in Iraq and work to prevent genocide and regional conflict. Who can say in advance exactly how many troops will be needed to do that? And if it emerges that al Qaeda in Iraq is reconstituting more quickly than expected, will Congress forbid President Bush—or President Clinton—from reinforcing American troops there on the grounds that it would violate the timelines? Would any American want Congress to do that, accepting the risk that a revitalizing al Qaeda in Iraq could prepare to attack Americans everywhere, including the U.S.?

It is perfectly natural for the American people and their leaders to want to have some idea of what the military command expects will be necessary to fight this war, and the commanders in Iraq have been regularly offering their views. Military staff, of course, must estimate force requirements and make plans to ensure that there will be adequate troops available for the best, worst, and most likely cases. But as soon as the discussion moves away from what the situation in Iraq requires, and focuses exclusively on arbitrary dates and number of forces, it forgets about protecting America’s interests and citizens and moves toward accepting defeat. Some Americans may prefer to accept defeat with its laundry list of consequences, but it is hard to believe that there are very many of them.

Frederick W. Kagan is a military historian and a resident scholar at the American Enterprise Institute.