Most historians of the Islamic State agree that the group emerged out of al-Qaeda in Iraq as a response to the U.S. invasion in 2003. They also agree that it was shaped primarily by a Jordanian jihadist and the eventual head of al-Qaeda in Iraq, Abu Musab al-Zarqawi. The Jordanian had a dark vision: He wished to fuel a civil war between Sunnis and Shiites and establish a caliphate. Although he was killed in 2006, his vision was realized in 2014—the year isis overran northern Iraq and eastern Syria.
Narratives about the origins of Islamic State ideology often focus on the fact that Zarqawi and Osama bin Laden, both Sunni extremists, diverged on the idea of fighting Shiites and on questions of takfir, or excommunication. Such differences, the story goes, were reinforced in Iraq and eventually led to the split between isis and al-Qaeda. Based on this set of assumptions, many conclude that Zarqawi must have provided the intellectual framework for isis.
Recently, I came to question the conventional wisdom. The groundwork for isiswas arguably laid long before the invasion, and if there was one person responsible for the group’s modus operandi, it was Abdulrahman al-Qaduli, an Iraqi from Nineveh better known by his nom de guerre, Abu Ali al-Anbari—not Zarqawi. It was Anbari, Zarqawi’s No. 2 in his al-Qaeda years, who defined the Islamic State’s radical approach more than any other person; his influence was more systematic, longer lasting, and deeper than that of Zarqawi.