As I've discussed repeatedly, historical analogies are (at best) revealing of contemporary events only up to a point. Once one takes it to a certain level of detail, these analogies inevitably become misleading. This phenomenon is nowhere more true than in parallels many (esp. on the left) draw between the American wars in Vietnam and Iraq.
Cunning Realist, however, makes a compelling case that even if Iraq is not a repetition of the folly of Vietnam the two conflicts certainly "rhyme". Part of the reason why CR's parallels are interesting is that they focus on the domestic American politics and meaning of the two wars (which are indeed disturbingly similar), rather than on the ideological or geopolitical context of the two wars (which could scarcely be more different).