And that leaves the third and final category—perhaps the least appalling but likely the largest and most important. Call them the Sunni Pragmatists. These people include Iraqi tribal sheikhs, whose allegiance to isis originates not in a cultish death wish but in a desire to win security and well-being, and who seem to be using the Psychopaths and the True Believers as convenient allies. From ISIS, the Pragmatists get a way to punish Baghdad for its long neglect of Sunni regions. From the Pragmatists, ISIS already got a greased path into Iraq that allowed their tiny force to cover large amounts of ground and fulfill the True Believers’ goal of rapid expansion, á la the forces of the Prophet Muhammad in the earliest days of Islam. ISIS’s expansion into Iraq happened quickly both because many Sunnis cooperated, and because the Shia-led central government had incredibly weak holds on northern, mostly Sunni cities like Mosul. I observed the dereliction of Iraqi army bases in Mosul in late 2012, and it was clear even then that a serious invading force would face roughly as much resistance as Clark W. Griswold and family faced taking over Wally World. To hold that territory, now that isis forces are spread thin 300 miles beyond Raqqa, will require ongoing buy-in from their local Sunni allies.

At least some of the Sunni Pragmatists are ex-Baathists—colleagues of Saddam Hussein who have survived to fight again. The Tikrit-based Naqshabandi militia controlled by Saddam’s vice president Izzat Ibrahim al Douri (a dead ringer for Bryan Cranston) has periodically allied with isis to fight the Shia government of Nuri al Maliki. Douri is a secular man, like his old boss, which shows just how cynical his alliance with the True Believers has been—and how much more malleable his motivations and goals are than those of his True Believing and Psychopathic counterparts.