For most of my adult life, the United States has been at war against radical jihadist groups. On September 11, 2001, I remember watching as smoke rose from the Pentagon. Initially, our response seemed clear: wipe out Al-Qaeda. However, 14 years later, not only does Al-Qaeda remain at large (although Osama bin Laden is thankfully dead), but jihadism has engulfed entire states in the Middle East.
When the Islamic State of Iraq and the Levant (ISIS) captured the Iraqi city of Mosul last June, it took many by surprise. This was Islamic radicalism, but not quite the same as Al-Qaeda. Whereas bin Laden had already become infamous before the 9/11 attacks, most Americans knew nothing about ISIS.