The Domestic Terrorist Threat: Background and Issues for Congress: Congressional Research Service, May 15, 2012

The emphasis of counterterrorism policy in the United States since Al Qaeda’s attacks of September 11, 2001 (9/11) has been on jihadist terrorism. However, in the last decade, domestic terrorists—people who commit crimes within the homeland and draw inspiration from U.S.-based extremist ideologies and movements—have killed American citizens and damaged property across the country. The U.S. government reacted to 9/11 by greatly enhancing its counterterrorism efforts. This report discusses how domestic terrorists broadly fit into this new counterterrorism landscape, a terrain that in the last 10 years has been largely shaped in response to terrorists inspired by foreign ideologies.