![Islamic State militants pass by a convoy, Tel Abyad, northeast Syria, May 4, 2015 (Militant website via AP).](https://www.worldpoliticsreview.com/wp-content/uploads/2015/06/l_is_syria_06052015.png?w=519&h=259&crop=1)
It’s not hard to understand what motivates local Iraqis and Syrians to fight for the self-proclaimed Islamic State (IS). Most believe they are defending their community, Sunni Arabs, against repression from the Alawite-dominated Syrian dictatorship or the Shiite-dominated Iraqi government. But the motives of the estimated 20,000 foreign fighters that have joined IS are more complex, tied to deep psychological factors that make them less amenable to political solutions and more difficult to address. Every insurgent movement includes people with diverse motives. Yet the counterinsurgency doctrine of the United States and its NATO partners gravitates to political and economic grievances, […]