Irbil is an ancient city in northern Iraq with some 1.5 million inhabitants. In the summer of 2014, that resident population was swollen by tens of thousands of Christians and Yazidis fleeing the advance of Islamic State (IS).For a perilous moment, these desperate fugitives came within a hair’s breadth of being overwhelmed in their place of sanctuary. By 8 August, IS fighters were only 25 miles outside Irbil. Having conquered the even larger city of Mosul, there was every possibility that Irbil would be next to fall into their pitiless grasp.But, in the space of a few hours, everything changed. A series of US air strikes destroyed the IS vanguard and lifted the threat to Irbil. During the breathing space that followed, Kurdish Peshmerga units were able to throw a protective cordon a