Twenty-five years after 9/11, the global jihadi movement is a shadow of the force that once seemed poised to reshape world politics. Daniel Byman assesses what the United States accomplished—and failed to accomplish—in the long war on terrorism. Washington suffered costly setbacks, most notably the disastrous invasion of Iraq and the grinding war in Afghanistan. Yet al-Qaeda was devastated, the Islamic State lost its territorial caliphate, and the catastrophic attacks many Americans feared after 9/11 never materialized. Perhaps most strikingly, global jihadism has lost much of the ideological momentum that once enabled it to mobilize recruits across continents.
This decline resulted from both sustained U.S. and allied pressure and the jihadis’ own failures. Intelligence cooperation, homeland-security improvements, attacks on terrorist safe havens, and partnerships with local forces steadily degraded terrorist networks. At the same time, jihadi groups alienated Muslim publics through indiscriminate violence, made enemies of nearly everyone, and—most spectacularly in the Islamic State’s case—overreached by trying to build and govern a caliphate.
The result is a paradoxical legacy: the United States may not have won the war on terrorism, but the jihadis clearly lost. The danger has not disappeared, particularly in weak states in Africa and the Middle East. The challenge now is to keep it contained without once again allowing counterterrorism to become an all-consuming American mission.
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