Suddenly, a common enemy has joined mutually distrustful players in the making of a coalition against ISIS—just the kind of multilateralism that the President favors. As this month’s events bore out, such an effort requires American leadership. Obama said as much in his August 7th speech, but it’s easy to sense his reluctance to get dragged back into the sinkhole of Iraq and the region. The speed with which he declared the Yazidi crisis over—while thousands of people, including those too old or too weak to walk, remain behind on Mt. Sinjar—suggested a desire to move on. Meanwhile, thousands of people from another beleaguered Iraqi minority—Shiite Turkmen—face destruction in the town of Amerli, near Kirkuk, under an ISIS siege. Tribal sheikhs in Anbar are fighting ISIS, and the provincial governor there has asked for American help against the jihadists. The risks of action are obvious; by now, the risks of inaction should be, too.