How Syria's Civil War Became a Holy Crusade

In this piece for Foreign Affairs, CISAC's Thomas Hegghammer and the Washington Institute for Near East Policy's Aaron Zelin estimate that violence in Syria will skyrocket due to an influx of foreign fighters. 

Egyptian theologian and top Sunni cleric Yusuf al-Qaradawi called for Sunni Muslims worldwide to fight in Syria against Bashar al-Assad, Hezbollah, and Shiite influence. Qaradawi's call, echoed by other prominent Sunni theologians, could inflame tensions and political differences across the region, and flood Syria with even more foreign fighters. Hegghammer and Zelin estimate that Syria has over 5,000 Sunni foreign fighters, the second-largest foreign-fighter destination in the history of modern Islamism, and that the number is slated to double in the near future.