Libya and Syria serve as parallel cases through which questions about the US’s role in the world are refracted. The standard narrative is as follows: the US intervened in Libya under the guise of preventing mass atrocities, this intervention ended first in regime change and then in a failed state, and Libyans now live in enduring danger; the US did not intervene to protect civilians during the Syrian Civil War, war snarled the full region into conflict, and today Syrian civilians continue to die in unspeakable ways and uncounted numbers. At each stage, the narrative is in fact more complicated, particularly if we begin by asking whether the US did in fact prevent mass atrocity in Libya and end by noting the U.S. did in fact intervene in Syria in multiple ways, but the broad lines are still instructive for understanding public debate. Would Libyans have been better off in the absence of an American-led intervention, or would they have been worse off? Would Syrians have been better off for U.S. intervention, or would they have been worse off for it?