Sen. John Fetterman (D-PA) drew attention to a new study this week highlighting the rise of left-wing terrorism in the United States, warning that inflammatory political rhetoric could contribute to further violence.
In a post on X, Fetterman shared [1] a screenshot of an Axios article titled “Study: Left-wing terrorism climbs to 30-year high.”
He emphasized that political violence has no justification.
“Unchecked extreme rhetoric, like labels as Hitler or fascist, will foment more extreme outcomes,” Fetterman wrote.
“Political violence is always wrong — no exceptions. We must all turn the temperature down.”
Unchecked extreme rhetoric, like labels as Hitler or fascist, will foment more extreme outcomes.
Political violence is always wrong—no exceptions.
We must all turn the temperature down. pic.twitter.com/PDwYjn4rfl [2]
— U.S. Senator John Fetterman (@SenFettermanPA) September 28, 2025 [3]
The Axios article summarized findings from the Center for Strategic & International Studies (CSIS), which analyzed a dataset of 750 domestic attacks and plots carried out between January 1, 1994, and July 4, 2025.
According to CSIS, left-wing terrorism reached its highest level in three decades during the first half of 2025.
The research found that while far-right violence has historically been more frequent, those incidents declined significantly in the first six months of this year.
Left-wing extremists, meanwhile, have carried out an increasing number of attacks.
Key findings of the report included:
- Left-wing extremists were responsible for 41 attacks since 2016, compared with 152 committed by right-wing extremists in the same period.
- Left-wing violence has resulted in 13 deaths over the past decade, while right-wing attacks accounted for 112 deaths, and jihadist violence led to 82 deaths.
- At least five left-wing plots or attacks were recorded in 2025 so far, compared with just one attributed to right-wing extremists.
The report’s release comes in the aftermath of the assassination of Turning Point USA founder Charlie Kirk on September 10 at Utah Valley University.
Kirk was killed while speaking at a student event.
Utah Governor Spencer Cox (R) disclosed that investigators found bullet casings in the shooter’s rifle etched with political messages, including the phrase: “Hey fascist! Catch!”
The killing intensified scrutiny over political rhetoric directed at conservative leaders.
Breitbart News reported that Democrats, including California Governor Gavin Newsom, have continued to use the label “fascist” to describe Trump administration officials such as White House Deputy Chief of Staff for Policy Stephen Miller.
The combination of the CSIS data and the assassination has heightened concerns about the rise of politically motivated violence from the left.
Law enforcement officials have pointed to the growing number of cases this year as evidence of a shifting domestic threat environment.
Fetterman’s remarks on X mark a rare public call from a Democratic senator to lower the temperature in political discourse and refrain from using extreme labels that could inflame tensions.
As of now, federal agencies have not issued additional public advisories following the release of the CSIS report.
However, the findings are expected to factor into ongoing debates about how to address politically motivated violence in the United States.