As best I can tell, David Petraeus’ doctoral dissertation on learning the lessons of Vietnam is, as Brian Beutler says, an exercise in saying nothing at extraordinary length. Check out the thesis paragraph of his conclusions section:
History in general, and the American experience in Vietnam in particular, have much to teach us, but both must be used with discretion and neither should be pushed too far. The Vietnam analogy, for all its value as the most recent large-scale use of American force abroad, has limits. Most importantly, the applicability of the lessons drawn from Vietnam, just like the applicability of lessons taken from any other past event, always will depend on the circumstances of the particular situation at hand.
That’s his conclusion. I even agree, but one would really hope for something firmer….