Which right-wing extremist groups were responsible for the most fatalities in the USA between 2015 and 2024?

Checked on September 19, 2025
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1. Summary of the results

The analyses provided suggest that right-wing extremist groups were responsible for the most fatalities in the USA between 2015 and 2024 [1] [2]. White supremacists are particularly noted as a significant threat, accounting for the majority of terrorist incidents and fatalities [1] [3]. The data also indicates that right-wing extremist violence has been responsible for approximately 75% to 80% of U.S. domestic terrorism deaths since 2001 [4]. Additionally, in 2024, all identified extremist-related murders were tied to right-wing extremism, with a significant portion involving white supremacists [3]. The National Terrorism Advisory System (NTAS) and various threats to the US homeland are also discussed, but specific information on right-wing extremist groups responsible for the most fatalities between 2015 and 2024 is not provided [5].

2. Missing context/alternative viewpoints

A key point missing from the original statement is the definition of right-wing extremist groups and how they are categorized [6]. The analyses also highlight the importance of considering domestic terrorism as a whole, rather than just focusing on right-wing extremism [6]. Furthermore, the motivations behind right-wing extremist violence, such as racial or ethnic motivations, are not fully explored in the original statement [6]. Alternative viewpoints, such as the role of left-wing extremist groups in domestic terrorism, are not presented in the analyses [2]. The START website provides extensive research and data on right-wing terrorism, which could be used to further analyze and understand the threat posed by these groups [7].

3. Potential misinformation/bias in the original statement

The original statement may be biased towards highlighting the threat of right-wing extremism, without providing a comprehensive view of domestic terrorism [6]. The statement may also be misleading in implying that all right-wing extremist groups are responsible for the most fatalities, when in fact, white supremacists and anti-government extremists are specifically noted as the most significant threats [3]. The CSIS brief and ADL report may benefit from this framing, as they are cited as sources that confirm the threat posed by right-wing extremist groups [1] [3]. However, the GAO report and Cato Institute may provide alternative perspectives on domestic terrorism, which could be used to present a more balanced view [6] [4].

Want to dive deeper?
What were the most deadly right-wing extremist attacks in the USA between 2015 and 2024?
How do US law enforcement agencies track and classify right-wing extremist groups?
Which right-wing extremist groups have been designated as domestic terrorist organizations by the US government?
What role do online platforms play in the radicalization and recruitment of right-wing extremists in the USA?
How have US counterterrorism strategies evolved to address right-wing extremism between 2015 and 2024?