Every time I hear about a massacre like last Friday’s in Houla, Syria, I think back to Srebrenica, the July 1995 Bosnian massacre that helped turn me—and many other post-Vietnam era journalists and policy types—into liberal hawks. Since then, humanitarian intervention has become a recurring feature of American foreign policy debates. After the disasters of Iraq and Afghanistan (no, they weren’t humanitarian interventions but they have sapped America’s capacity and stomach for war), I’d have thought discussions of humanitarian intervention might go the way of the dodo bird. They haven’t.