What We Still Don’t Know About the Islamic State’s Foreign Fighters

The Barcelona attackers killed 14 people—a middling tally for an ISIS attack in Europe. Watch one of the attackers prancing around like an idiot on the streets of Cambrils, Spain, before being shot dead by police, and you can see why the death toll might not have been higher. These do not appear to be trained commandos, moving calmly and tactically like the Bataclan attackers in November 2015. They are amateurs, and if they had any training at all, it doesn’t show.

The biggest concern for counterterrorism officials, and indeed anyone interested in not being blown to smithereens in a Brussels subway or shot dead in a Parisian theater, is the returned foreign fighters—those who went to Syria, were taught to kill, and have returned to their home countries. Since we still don’t know much about this population, and still less about those who have come back, every last morsel of information about them deserves close scrutiny.