What is the Islamic State?

Where did it come from, and what are its intentions? The simplicity of these questions can be deceiving, and few Western leaders seem to know the answers. In December, The New York Times published confidential comments by Major General Michael K. Nagata, the Special Operations commander for the United States in the Middle East, admitting that he had hardly begun figuring out the Islamic State’s appeal. “We have not defeated the idea,” he said. “We do not even understand the idea.” In the past year, President Obama has referred to the Islamic State, variously, as “not Islamic” and as al-Qaeda’s “jayvee team,” statements that reflected confusion about the group, and may have contributed to significant strategic errors.

The group seized Mosul, Iraq, last June, and already rules an area larger than the United Kingdom. Abu Bakr al-Baghdadi has been its leader since May 2010, but until last summer, his most recent known appearance on film was a grainy mug shot from a stay in U.S. captivity at Camp Bucca during the occupation of Iraq. Then, on July 5 of last year, he stepped into the pulpit of the Great Mosque of al-Nuri in Mosul, to deliver a Ramadan sermon as the first caliph in generations—upgrading his resolution from grainy to high-definition, and his position from hunted guerrilla to commander of all Muslims. The inflow of jihadists that followed, from around the world, was unprecedented in its pace and volume, and is continuing.

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.

The Islamic State, also known as the Islamic State of Iraq and al-Sham (ISIS), follows a distinctive variety of Islam whose beliefs about the path to the Day of Judgment matter to its strategy, and can help the West know its enemy and predict its behavior. Its rise to power is less like the triumph of the Muslim Brotherhood in Egypt (a group whose leaders the Islamic State considers apostates) than like the realization of a dystopian alternate reality in which David Koresh or Jim Jones survived to wield absolute power over not just a few hundred people, but some 8 million.

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.

Bin Laden viewed his terrorism as a prologue to a caliphate he did not expect to see in his lifetime. His organization was flexible, operating as a geographically diffuse network of autonomous cells. The Islamic State, by contrast, requires territory to remain legitimate, and a top-down structure to rule it. (Its bureaucracy is divided into civil and military arms, and its territory into provinces.)

We are misled in a second way, by a well-intentioned but dishonest campaign to deny the Islamic State’s medieval religious nature. Peter Bergen, who produced the first interview with bin Laden in 1997, titled his first book Holy War, Inc. in part to acknowledge bin Laden as a creature of the modern secular world. Bin Laden corporatized terror and franchised it out. He requested specific political concessions, such as the withdrawal of U.S. forces from Saudi Arabia. His foot soldiers navigated the modern world confidently. On Mohamed Atta’s last full day of life, he shopped at Walmart and ate dinner at Pizza Hut.