An arc of instability stretching across Africa's Sahel region, an area of strategic interest for the United States and its allies, is plagued by violent extremist organizations (VEOs). These organizations, including Boko Haram, al Qaeda, and other terror groups, have metastasized and present a serious threat to regional stability. Now these VEOs are transitioning. Under sustained pressure from French and regional security forces, and reeling from the loss of senior leaders, many of these groups feel backed into a corner. Despite setbacks, these groups continue to plague the region. To enhance policymakers' understanding of these threats and how to respond to them, CSIS experts from the Africa Program and Transnational Threats Project conducted field-based and scholarly research examining the broad range of factors at play in the region. This research provides little ground for optimism. Chronic underdevelopment, political alienation, failed governance and corruption, organized crime, and spillover from Libya help foster and sustain violent extremists throughout the Sahel.