Samantha Power, the U.S. ambassador to the United Nations, recently cautioned Americans against intervention fatigue: “I think there is too much of ‘Oh, look, this is what intervention has wrought’ . . . one has to be careful about overdrawing lessons.” Say what? Given the calamities wrought in Iraq, Libya and now Ukraine, one would think that a fundamental rethinking and learning of lessons is long overdue. The United States needs a sober look at the actual costs of supposed good intentions divorced from realism.