The jihadists’ new chief, Abu Bakr al-Baghdadi, was a man of soaring ambitions, but in late 2011, well into his second year as leader, his boasts were as empty as the group’s coffers. The Islamic State of Iraq lacked resources, fighters, and sanctuary. And, perhaps most critically, it lacked a cause—a single big idea with which it could rally its depleted forces and draw other Muslims into the fold. Soon, within the chaos of revolutionary Syria, it would find all four.
