ARGUMENT: UNSUPPORTED CONCLUSIONSCorrectly Assessing Left-Wing Terrorism and Political Violence in the United States
A recent CSIS report, making sweeping claims about a supposed rise in leftwing terrorism in the United States, risks feeding false narratives about political violence and polarization. Michael Jensen and Amy Cooter write that the evidence used to sound this alarm consists of just five plots and attacks, and that these five events not only “are doing a lot of heavy lifting” in the report, but that they are given “an unwarranted level of causal and predictive power.” This tiny sample “simply does not justify inducing panic with eye-popping headlines.”
A recent report published by the Center for Strategic and International Studies (CSIS), Left-Wing Terrorism and Political Violence in the United States, risks feeding false narratives about political violence and polarization. The report’s authors, Daniel Byman and Riley McCabe, make a sweeping claim: 2025 is on “pace to be the left’s most violent year in more than three decades” and left-wing terrorism is “on track…to reach historically high levels.”
Michael Jensen and Amy Cooter write in Just Security that the evidence used to sound this alarm consists of just five plots and attacks that occurred over a nearly seven-month period this year. According to the data presented in the report, these events represent a 400 percent increase in far-left plots and attacks from last year.
Jensen and Cooter add:
But the CSIS study suffers from fatal analytic flaws. For starters, like shark attacks, the number of events attributed to left-wing terrorism this year is so low in absolute terms that it simply does not justify inducing panic with eye-popping headlines.
Indeed, these five events are doing a lot of heavy lifting in Byman and McCabe’s analysis. They are given an unwarranted level of causal and predictive power. For instance, while the report clearly specifies the authors are analyzing attacks “so far” in 2025, elements of the data presentation leave the piece open to interpretation, implying these events are a forecast of what is to come. The opening paragraphs alert readers that “2025 marks the first time in more than 30 years that left-wing attacks outnumber those from the far right.” The authors compare the number of left-wing events to both right-wing and jihadist attacks and plots, arguing that the latter two types of threats have declined. This pronouncement is, at best, premature, given that a quarter of the year remains.
It is also misleading. Consider that according to the authors’ own data, 13 victims died as a result of left-wing attacks from 2016 through the first six-plus months of 2025. During that same time period, 82 victims perished in jihadist attacks, while 112 people were killed in right-wing attacks. In fact, 14 people were killed in an ISIS-inspired car ramming attack on Bourbon Street in New Orleans on New Year’s Day 2025 alone – more than all those who perished in left-wing attacks inside the United States in the last nine-plus years.
