This is a problem. Chaotic Evil death cults are, of course, horrid: but they also can be slaughtered with relative impunity. Lawful Evil cults, on the other hand, tend to want to stick around for a while. As we are seeing in the Middle East right now.
While no one is predicting that the Islamic State will become steward of an accountable, functioning state anytime soon, the group is putting in place the kinds of measures associated with governance: issuing identification cards for residents, promulgating fishing guidelines to preserve stocks, requiring that cars carry tool kits for emergencies. That transition may demand that the West rethink its military-first approach to combating the group.