Lesson No. 4 is that even superpowers have to talk to bad guys. The absence of a diplomatic relationship with Iran and the deterioration of the one with Syria -- two countries that bear enormous responsibility for the current crisis -- leave the United States with fewer options and levers than might otherwise have been the case. Distasteful as it might have been to have or to maintain open and normal relations with such states, the absence of such relations ensures that we will have more blind spots than we can afford and that we will have to deal through surrogates on issues of vital importance to the United States. We will have to get over the notion that talking to bad guys somehow rewards them or is a sign of weakness. As a superpower, we ought to be able to communicate in a way that signals our strength and self-confidence.This is a long-standing US policy - that ignoring certain regimes is a perfectly good substitute for accepting reality. To be totally fair to Bush, previous presidents have done the same thing. Nonetheless, it's childish and self-defeating.
Of course, if America actually tried talking to outlaw regimes, it might not have to go to war for no reason whatsoever. And that, obviously, would be a tragedy.