A long read from The Atlantic but well worth it:

Our ignorance of the Islamic State is in some ways understandable: It is a hermit kingdom; few have gone there and returned. Baghdadi has spoken on camera only once. But his address, and the Islamic State’s countless other propaganda videos and encyclicals, are online, and the caliphate’s supporters have toiled mightily to make their project knowable. We can gather that their state rejects peace as a matter of principle; that it hungers for genocide; that its religious views make it constitutionally incapable of certain types of change, even if that change might ensure its survival; and that it considers itself a harbinger of—and headline player in—the imminent end of the world.

We have misunderstood the nature of the Islamic State in at least two ways. First, we tend to see jihadism as monolithic, and to apply the logic of al‑Qaeda to an organization that has decisively eclipsed it. The Islamic State supporters I spoke with still refer to Osama bin Laden as “Sheikh Osama,” a title of honor. But jihadism has evolved since al-Qaeda’s heyday, from about 1998 to 2003, and many jihadists disdain the group’s priorities and current leadership.