"The Islamic State is a byproduct of the 2003 American intervention in Iraq and the subsequent American departure in 2011. At its peak in late 2014, the group held more than 100,000 square kilometers of territory with a population of nearly 12 million, mostly in Iraq and Syria. Beginning in 2015, the Islamic State began to lose territory as it faced increasingly effective resistance. Still, the Islamic State continues to conduct and inspire attacks around the world. This report assesses the threat the Islamic State poses to the United States and examines four possible strategies to counter the group: disengagement, containment, rollback 'light' (with a reliance on local forces backed by U.S. special operations forces, Central Intelligence Agency and other intelligence assets, and airpower), and rollback 'heavy' (adding the employment of American conventional forces in ground combat). The authors conclude that the United States should pursue a light rollback strategy.

They also recommend additional steps, such as rebalancing counterterrorism efforts to address grievances, loosening restrictions on U.S. military operations, increasing U.S. military posture in Africa, and tightening restrictions in the Islamic State's internet access."--Publisher's web site.