Jihadism has evolved dramatically and traumatically since the 9/11 attacks. Movements, leaders, targets, tactics, and arenas of operation have all proliferated in ways unimagined in 2001. The international community has mobilized unprecedented force against an array of jihadis, with mixed results. The United States alone has spent trillions of dollars – in military campaigns, intelligence, law enforcement, homeland security, and diplomacy – to counter jihadism. Progress has been made; fewer than a hundred people were killed inside the United States between 2001 and late 2016 – in stark contract to the death toll on 9/11. Yet the threat endures.
The emergence of the Islamic State – also known as ISIS, ISIL, of Daesh – transformed the world of jihadism. After capturing large swaths of Iraq and Syria in 2014, the Islamic State attracted tens of thousands of foreigners who sought to build a new Islamic society in a modern caliphate. They included engineers, accountants, teachers, grandparents, and teen-age girls, as well as fighters. They reinvigorated existing jihadist movements and galvanized a new wave of support for jihadism generally. In 2014, ISIS seemed to eclipse al-Qaeda.