Fact check: Who has been responsible for more fatalities as a result of Political violence in the United States over the past 30 years - the Left or the Right?

1. Summary of the results

The question of who has been responsible for more fatalities as a result of political violence in the United States over the past 30 years is complex and multifaceted. According to an analysis by ^[1], right-wing terrorists have accounted for 11% of murders, while left-wing terrorists have accounted for about 2% from 1975 to 2025. However, if the 9/11 attacks are excluded, the numbers change significantly, with right-wing terrorists accounting for 63% of murders and left-wing terrorists accounting for 10% ^[1]. Another analysis by ^[1] reports that since 1975, 3,599 people have been murdered in politically motivated terrorist attacks in the United States, with 87% of those murders committed by terrorists inspired by Islamist ideology, and 11% by right-wing terrorists ^[1]. Excluding the 9/11 attacks, the number of murders reduces to 620, with right-wing terrorists accounting for 63% of the murders, and left-wing terrorists accounting for 10% ^[1]. The ADL Center on Extremism also reports that in 2024, domestic extremists killed at least 13 people in the United States, with the majority of the murders connected to right-wing extremism ^[2]. Overall, the data suggests that right-wing extremism has been responsible for a greater number of fatalities in the United States over the past 30 years.

2. Missing context/alternative viewpoints

A key piece of missing context is the definition of "left-wing" and "right-wing" extremism, as different sources may have different criteria for classification ^[3]. Additionally, the role of Islamist ideology in politically motivated violence is significant, accounting for 87% of murders since 1975 ^[1]. The rise of political violence in the United States is also linked to the increasing polarization of American society, with the sorting of people into distinct identity groups and the erosion of cross-cutting ties ^[4]. Another alternative viewpoint is that Americans express roughly equal levels of concern about left-wing and right-wing extremism and violence, with a majority of respondents believing that political violence is increasing and is never justified ^[5]. The complexities of political violence in the United States cannot be reduced to a simple left-right dichotomy, and a more nuanced understanding of the factors contributing to violence is necessary.

3. Potential misinformation/bias in the original statement

The original statement may be misleading in its implication that political violence in the United States can be attributed solely to either the Left or the Right ^[3]. The data suggests that right-wing extremism has been responsible for a greater number of fatalities, but this does not necessarily mean that the Left is not also responsible for violence. The ADL Center on Extremism reports that the trend of right-wing extremists committing the majority of extremist-related murders has continued for several years ^[2], which may benefit those who seek to emphasize the threat of right-wing extremism. On the other hand, the fact that Americans express roughly equal levels of concern about left-wing and right-wing extremism and violence ^[5] may benefit those who seek to downplay the threat of right-wing extremism. Ultimately, a nuanced understanding of the complexities of political violence in the United States is necessary to avoid misinformation and bias ^[4].