Why can’t America win a war these days?

With the 10th anniversary of the invasion of Iraq this week, it seems a worthwhile time to reflect on the fact that for all its obvious military advantages over every country on the planet, the United States doesn’t seem particularly good at winning wars anymore. 

In her book-length study, Who Wins: Predicting Strategic Success and Failure in Armed Conflict, University of North Carolina political scientist Patricia L. Sullivan writes:

"The United States failed to achieve its primary political objectives in approximately 30 percent of its major military operation between 1946 and 2002. In almost every one of these failues, the United States chose to terminate its military intervenion short of victory despite the fact that it retained an overwhelming physical capacity to sustain military operations. The U.S. withdrawal from Somalia after the death of sixteen Army Rangers may appear to be an extreme case, but it is consistent with a pattern in which the United States experienced higher-than-expected costs and withdrew its troops short of attaining intervention objectives, despite the fact that its military was, at most, only marginally degraded in the conflict. The United States’ unsuccessful intervention in Vietnam is, of course, the quintessential example. "

Sullivan argues that the most important factor in predicting whether a country will be successful in initiating military conflict is not its relative military might or prosperity compared to its opponent, or even it’s "resolve" to keep up the fight in the face of high casualties, but the goals and expectations it has going into the conflict. She writest that superior firepower is less of an advantage the more the attacker’s war aims require its opponents to change its behavior:

Powerful states do not lose small wars simply because they have less cost tolerance than their weak adversaries. The extent to which a physically weaker actor’s cost-tolerance advantage can affect armed conflict outcomes is largely a function of the degree to which the stronger actor has war aims that require the weak actor to change its behavior. The balance of military capabilities between the belligerents is expected to be the most important determinant of outcomes when the objects at stake can be seized and held with physical force alone. The defender’s tolerance for costs becomes more significant when a challenger pursues political objectives that require a change in target behavior. 

Operation Desert Storm was an example of the first type of objective. Despite Saddam Hussein’s warning to the United States that "yours is a society which cannot accept 10,000 dead in one battle," the war was over must faster than even U.S. miltary planners expected. The expulsion of Iraqi forces from Kuwait was a goal that could be accomplished through brute force alone, and the U.S. military advantage was decisive. This was true of Saddam’s initial ouster in 2003 as well.

But, Sullivan argues, following the ouster of Iraq, the second Bush administration vastly overestimated the usefulness of its firepower advantage in supporting the new Iraqi government against a growing domestic insurgency.

The book’s conclusions aren’t exactly shocking in the post-Iraq era — the field of counterinsurgency studies is devoted largely to the question of how to affect a population’s behavior in situations where firepower isn’t an advantage — but judging by the news out of Mali, it’s not clear that militarily-superior western power have exactly learned the lesson.