After more than a decade of combating Al Qaeda in Afghanistan and Pakistan, the United States now faces an increasingly diverse threat from Al Qaeda affiliates in the Middle East and Africa and from emerging groups that have adopted aspects of Al Qaeda's ideology but operate relatively or completely autonomously from the group's senior leadership. U.S. counterterrorism debates have focused on "formal" Al Qaeda affiliates, and policymakers increasingly are considering options for addressing the range of threats posed by the wider spectrum of groups inspired by-or similar in goals and aspirations to-Al Qaeda. An additional challenge is the fluid nature of the threat, given the apparent fragmentation of Al Qaeda, and Ayman al Zawahiri's struggle to assert leadership of the group in light of challengers such as Islamic State leader Abu Bakr al Baghdadi. Finally, concerns regarding these issues might shape ongoing reevaluations of the federal statutes that underpin current U.S. counterterrorism policy, including the 2001 Authorization for Use of Military Force (AUMF, P.L. 107-40). In addition to the AUMF, Congress has addressed the emergence of Al Qaeda affiliates through a number of channels, including oversight of executive branch counterterrorism policies and practices; authorization and appropriations of U.S. funds for counterterrorism operations; and assistance for partner nations engaged in such operations. Note: In addition to focusing on Al Qaeda affiliates, or groups that have publicly sworn allegiance to Al Qaeda leadership and been formally accepted as affiliates, this report also profiles a selection of other groups such as the Islamic State (formerly known as ISIL or ISIS) and Boko Haram.