When I taught American foreign policy, I always began my lectures on Vietnam by showing the class Lesson No. 9 from "The Fog of War," Errol Morris' penetrating documentary about former Secretary of Defense Robert Strange McNamara. The lesson? In order to do good, you may have to engage in evil. Undoubtedly, that contradictory logic has justified some of the United States' most ferocious acts abroad. The nuclear attacks on Hiroshima and Nagasaki, and the bombing of North Vietnam, are two extreme examples.
Immediately after the clip ended, I would survey the 40-odd college students' faces looking up at me for a conclusion. Without fail, some were disgusted, some were confused, and always, some were proud. Instead of answering them, I would ask, Are McNamara's actions excusable? ...