Those urges and impulses are deeply rooted in American history and, thus, in American habits of thinking. Occasionally, as after the Vietnam War, the sheer magnitude of the costs has led to a temporary departure from those habits.

Given the nature of the current debate, such a departure does not appear forthcoming. Quite the contrary. The United States appears destined, for reasons related to what makes it exceptional, to continue using military force beyond what serves its interests. It will take exceptional leadership to limit the resulting damage.

Paul R. Pillar is a contributing editor at the National Interest and the author most recently of Why America Misunderstands the World.

Image: U.S. Army soldiers in Al Muradia village, Iraq. Flickr/U.S. Army.