Domestic terrorismThreats of violent Islamist and far-right extremism: What does the research say?

By William Parkin, Brent Klein, Jeff Gruenewald, Joshua D. Freilich, and Steven Chermak

Published 23 February 2017

The 9/11 attacks were perpetrated by Islamist extremists, resulting in nearly 18 times more deaths than America’s second most devastating terrorist attack – the Oklahoma City bombing. More than any other terrorist event in U.S. history, 9/11 drives Americans’ perspectives on who and what ideologies are associated with violent extremism. But focusing solely on Islamist extremism when investigating, researching and developing counterterrorism policies goes against what the numbers tell us. Far-right extremism also poses a significant threat to the lives and well-being of Americans. This risk is often ignored or underestimated because of the devastating impact of the 9/11 terrorist attacks.It remains imperative to support policies, programs, and research aimed at countering all forms of violent extremism.

On a Tuesday morning in September 2001, the American experience with terrorism was fundamentally altered. Two thousand, nine hundred and ninety-six people were murdered in New York, Virginia and Pennsylvania. Thousands more, including many first responders, lost their lives to health complications from working at or being near Ground Zero.

The 9/11 attacks were perpetrated by Islamist extremists, resulting in nearly eighteen times more deaths than America’s second most devastating terrorist attack – the Oklahoma City bombing. More than any other terrorist event in U.S. history, 9/11 drives Americans’ perspectives on who and what ideologies are associated with violent extremism.

But focusing solely on Islamist extremism when investigating, researching and developing counterterrorism policies goes against what the numbers tell us. Far-right extremism also poses a significant threat to the lives and well-being of Americans. This risk is often ignored or underestimated because of the devastating impact of the 9/11 terrorist attacks.

We have spent more than ten years collecting and analyzing empirical data that show us how these ideologies vary in important ways that can inform policy decisions. Our conclusion is that a “one size fits all” approach to countering violent extremism may not be effective.

By the numbers
Historically, the United States has been home to adherents of many types of extremist ideologies. The two current most prominent threats are motivated by Islamist extremism and far-right extremism.

To help assess these threats, the Department of Homeland Security and recently the Department of Justice have funded the Extremist Crime Database to collect data on crimes committed by ideologically motivated extremists in the United States. The results of our analyses are published in peer-reviewed journals and on the website for the National Consortium for the Study of Terrorism & Responses to Terrorism.

The ECDB includes data on ideologically motivated homicides committed by both Islamist extremists and far-right extremists going back more than twenty-five years.

Between 1990 and 2014, the ECDB has identified 38 homicide events motivated by Islamist extremism that killed 62 people. When you include 9/11, those numbers jump dramatically to 39 homicide events and 3,058 killed.

The database also identified 177 homicide events motivated by far-right extremism, with 245 killed. And when you include the Oklahoma City bombing, it rises to 178 homicide events and 413 killed.