The Unseemly Side of Small Wars

Now that the United States has ended its military presence in Afghanistan on unfavorable terms, one wonders what it takes to win a war like this. The answer is not encouraging, and serves as a reminder that the United States should be picky about when to engage in wars against weaker foes in faraway places, and for how long.

Over the past 20 years, the United States has found itself trying to defeat insurgents, small groups of uniform-optional fighters who use hit-and-run tactics as they work to gather strength until they can overwhelm the state. During the surge in Iraq, Gen. David Petraeus and like-minded colleagues laid out a modern version of the "hearts and minds" model — the idea that if the forces fighting insurgents can win over enough of a population with good governance, they can rob the insurgents of a base of support.

As the good governance crowd acknowledges, counterinsurgency unavoidably entails nation-building. They are less clear about how violent the process can be....