Much of what ISIS has done clearly contradicts the moral intuitions and principles of many of its supporters. And we sense—through Hassan Hassan and Michael Weiss’s careful interviews—that its supporters are at least partially aware of this contradiction. Again, we can list the different external groups that have provided funding and support to ISIS. But there are no logical connections of ideology, identity, or interests that should link Iran, the Taliban, and the Baathists to one another or to ISIS. Rather, each case suggests that institutions that are starkly divided in theology, politics, and culture perpetually improvise lethal and even self-defeating partnerships of convenience.

The thinkers, tacticians, soldiers, and leaders of the movement we know as ISIS are not great strategists; their policies are often haphazard, reckless, even preposterous; regardless of whether their government is, as some argue, skillful, or as others imply, hapless, it is not delivering genuine economic growth or sustainable social justice. The theology, principles, and ethics of the ISIS leaders are neither robust nor defensible. Our analytical spade hits bedrock very fast.

I have often been tempted to argue that we simply need more and better information. But that is to underestimate the alien and bewildering nature of this phenomenon. To take only one example, five years ago not even the most austere Salafi theorists advocated the reintroduction of slavery; but ISIS has in fact imposed it. Nothing since the triumph of the Vandals in Roman North Africa has seemed so sudden, incomprehensible, and difficult to reverse as the rise of ISIS. None of our analysts, soldiers, diplomats, intelligence officers, politicians, or journalists has yet produced an explanation rich enough—even in hindsight—to have predicted the movement’s rise.