A Department of Homeland Security Center of Excellence led by the University of Maryland

A consortium of researchers dedicated to improving the understanding of the human causes and consequences of terrorism

Ideological Motivations of Terrorism in the United States, 1970-2016

Ideological Motivations of Terrorism in the United States, 1970-2016


Between 1970 and 2016 terrorist attacks in the United States were motivated by a variety of ideological perspectives. This background report presents information from the Global Terrorism Database (GTD) on terrorist attacks classified by ideology as part of the Terrorism and Extremist Violence in the United States (TEVUS) project.

Terrorism is a narrowly defined type of violence, even within the broader spectrum of ideologically motivated violence. The GTD defines terrorism as the threatened or actual use of illegal force and violence by a non-state actor to attain a political, economic, religious, or social goal through fear, coercion, or intimidation. In the application of this definition, the database does not include unsubstantiated threats, nor does it include plots or conspiracies that the perpetrators did not attempt to execute. The GTD does not include acts that occurred in the context of a law enforcement operation, such as a traffic stop or warrant execution. The GTD does not typically include violence stemming from interactions that were spontaneous or reactive. This might include clashes erupting at protests or riots, or violent hate crimes. The GTD does not include violence carried out by state actors.

Note that classification of terrorist attacks by ideology can be unclear, particularly when perpetrators of attacks identify with more than one ideological group or perspective, which may or may not be relevant to the motivations for the attack itself. The classification of terrorist activity by ideology does not characterize an entire population or ideological movement as violent or predisposed to use terrorist tactics to advance ideological beliefs.

Publication Information

Full Citation: 

Miller, Erin. 2017. "Ideological Motivations of Terrorism in the United States, 1970-2016." College Park, Maryland. November.

START Author(s): 
Erin Miller
Publication URL: 
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