Terrorism and Irregular Warfare

Contemporary jihadist terrorism traces an organizational evolution from al-Qaeda, founded by Osama bin Laden in the late 1980s and responsible for the 11 September 2001 attacks on the United States that killed nearly 3,000 people and triggered the US-led "war on terror," to its splinter, the Islamic State (also called ISIS or ISIL), which broke from al-Qaeda in 2014 and pursued a strategy of seizing and governing territory as a self-declared "caliphate" rather than operating purely as a clandestine network. Following the Islamic State's territorial defeat, jihadist violence has increasingly decentralized into a network of regional affiliates — including groups in the Sahel, Somalia (al-Shabaab, an al-Qaeda affiliate), and Afghanistan/Pakistan (ISIS-Khorasan) — that operate with varying degrees of autonomy from any central leadership and often exploit local grievances, weak governance, and existing conflicts rather than directing attacks from a unified command. Analysts, including those at the Council on Foreign Relations and the International Crisis Group, generally note that the most lethal and expansive contemporary jihadist violence now occurs in Sub-Saharan Africa rather than in the Middle East or South Asia, a shift from the geographic center of gravity in the 2000s and early 2010s.