"The [US] has never taken counterinsurgency seriously. The Army's doctrine hasn't changed since the 1840's." - John Waghelstein, a retired colonel in the Special Forces who helped to conduct the American-backed counterinsurgency campaign in El Salvador, quoted in The Fall of the Warrior King.
One of the most telling lines from Lt. Col. Nathan Sassaman, the star soldier and quarterback, is "Don't they have those people [who do nation-building] at the State Department?"
Well, yes, exactly.
(see also Leadership Failure, from Human Rights Watch)