In seeking to explain the drop in right-wing incidents, researchers speculated that, because of the Trump Administration policies on immigration and diversity programmes, “it is probable that at least some extremists do not feel the need to act violently”.
While the number of right-wing incidents dropped, the researchers said, the number of left-wing incidents rose.
“What our data shows us is that indeed left-wing violence has risen in the last 10 years and that 2025 marks the first time left-wing incidents have outnumbered those from the violent far-right,” said Riley McCabe, an associate fellow at CSIS and co-author of the research.
As political polarisation has deepened across the US in recent years, social scientists have been tallying and categorising incidents of domestic terror, informing a debate that itself has become political: Which side spawns more violence?
This month’s killing of Charlie Kirk, the conservative speaker, has inflamed that debate. On Tuesday, in the wake of the Kirk memorial, US President Donald Trump signed an executive order designating “antifa” - the decentralised, leftist movement - as a “domestic terrorist organisation”.
Then, yesterday, a fatal shooting at a Dallas Immigration and Customs Enforcement facility spurred Trump and Vice-President JD Vance to take aim again at Democrats, with Trump identifying “radical leftists” as the cause.
The CSIS researchers defined terrorism as the use or threat of premeditated violence by non-state attackers “with the intent to achieve political goals by creating a broad psychological impact”.
Events categorised as left-wing included those motivated by support for environmental causes, black nationalism, LGBTQ+ rights, anti-fascist rhetoric or opposition to capitalism, imperialism, or colonialism.
Events categorised as right-wing included those motivated by notions of racial or ethnic supremacy, opposition to government authority, opposition to abortion, the QAnon conspiracy theory and hatred based on sexuality or gender identity.
In all, they compiled a dataset of 750 terrorist attacks and plots in the United States from January 1994 through July 4, 2025. They collected incidents from academic databases, federal law enforcement press releases and news accounts.
What makes the reversal in the character of political violence so striking is that over the last 30 years right-wing incidents have far outnumbered those from the left-wing. Over the last 10 years, right-wing incidents sometimes outpaced left-wing incidents by a three-to-one margin.
Left-wing attacks rise
This year, however, the researchers said that left-wing incidents are on track to exceed any levels seen in the last 30 years, continuing a “noticeable” rise that they date to the 2016 election of Trump.
From 1994 through 2000, the researchers counted less than one left-wing terror incident a year.
That figure rose somewhat in the next decade. Since 2016, however, the numbers began to grow substantially.
From 2016 to 2024, they averaged 4.0 a year, the researchers said.
This year, counting to July 4 - a time frame that excludes both the Kirk assassination and yesterday’s attack on the ICE facility - there have been five left-wing attacks or plots, which sets a trajectory for a record-breaking year over the last three decades, they said.
The previous peaks were 2020 and 2022 when researchers counted eight left-wing attacks a year.
“We think the rise is driven by opposition to the Trump Administration and partisan extremism,” McCabe said. “I don’t think these sentiments are going to go away soon.”
Right-wing attacks wane
Even more striking than the rise in left-wing incidents is the sudden drop in right-wing incidents.
From 2011 through 2024, researchers counted an average of 20 right-wing incidents a year.
In the first half of 2025, however, they counted only one right-wing terrorist incident in the US - the June killing of Minnesota state legislator Melissa Hortman and her husband.
In trying to understand the reasons for the decrease in right-wing incidents, the researchers noted that the investigation of the January 6, 2021, Capitol attack likely caused disarray among right-wing extremists.
With that investigation, the US Government brought charges against more than 1000 people, including many affiliated with the Oath Keepers and Proud Boys.
At the same time, researchers noted, many of the Trump Administration’s policies likely suit many on the far-right.
Their report quotes Enrique Tarrio, the former Proud Boys leader pardoned by Trump: “Honestly, what do we have to complain about these days?” he said.
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