The number of right-wing terror attacks in the U.S. plunged dramatically in the first half of 2025, while the amount of political violence from the left creeped up, a new study found.
The report on terrorism and political violence by the Center for Strategic and International Studies, a bipartisan research group, found that, through July 4, "2025 marks the first time in more than 30 years that left-wing terrorist attacks outnumber those from the violent far right."
The study noted there had been one right-wing terrorist incident this year -- the June murder of Minnesota state legislator Melissa Hortman and her husband.
The report, written by the Washington think tank's Daniel Byman and Riley McCabe, called that number "a remarkable drop off."
Their analysis reviewed terror attacks and plots, which they defined as "the deliberate use or threat of premeditated violence by nonstate actors with the intent to achieve political goals by creating a broad psychological impact."
From 2011 through 2024, an average of 20 right-wing terror incidents took place each year, compared to an average of nearly three left-wing incidents annually during that same period.
The report also found that the average number of left-wing incidents was two per year from 2011 to 2015, and then an average of four per year from 2016 to 2024.
"It's important to note it's risen from very low levels and remains at very low levels," McCabe told NBC News.
In the past decade, left-wing attacks killed 13 victims, the report found, compared to 112 by right-wing attacks in the same time period.
The study, which uses data through July 4 -- before the assassination of conservative activist Charlie Kirk and Wednesday's attack on an ICE facility in Dallas -- found there had been five left-wing attacks and plots so far this year. That "puts 2025 on pace to be the left's most violent year in more than three decades," it said.
The report suggests the drop in right-wing incidents may be tied to President Donald Trump's 2024 election win.
"Although it is impossible to definitively prove the link between the policies of and positions championed in Trump's second term and the decline in right-wing terrorism incidents in the United States, it is probable that at least some extremists do not feel the need to act violently if their concerns are being addressed," the report says, citing the administration's "aggressive" actions on immigration, targeting of the "deep state" and crackdown on diversity initiatives.
"In addition, Trump's victory temporarily ended many concerns about a Democrat-orchestrated 'stolen election,' a leading conspiracy that motivated many extremists in the past," the study says.
Conversely, "left-wing violence has risen in the last 10 years" particularly since "Trump's rise to political prominence," the study says, and has generally targeted government and law enforcement.
"The rise on the left has been driven by a combination of anti-government extremism and partisan extremism," McCabe said, and "their opposition to the Trump administration fuels the attacks against the political leadership and the institutions that carry out the president's agenda."
Of the 41 left-wing incidents since 2016, anti-government extremism motivated 17, and partisan extremism motivated another 11, the study said.
Left-wing attacks have typically been less lethal than the right-wing ones, with two fatalities since 2020. The report counts the December 2024 assassination of UnitedHealthcare CEO Brian Thompson in New York City as one of those two fatal attacks.
The report was compiled using a dataset of 750 terrorist attacks and plots, as defined by the researchers, between Jan. 1, 1994, and July 4. Political attacks where the assailant's motive was mixed or unclear -- including the July 2024 attempted assassination of Trump in Butler, Pennsylvania -- were not included in the left/right data.
Butler shooter Thomas Crooks, the report noted, had searched online for locations where Trump or then-President Joe Biden would be publicly speaking, and while "it is possible Crooks had political motives, FBI reports and journalist investigations suggest the explanation was more likely a mix of personal issues."
The report also excluded some other high-profile incidents, including an arson attack on Pennsylvania Gov. Josh Shapiro's residence and a shooting that killed two Israeli Embassy staff in Washington, D.C., because they were classified as "ethnonationalist incidents."
Jared Holt, a senior researcher at Open Measures who monitors online extremism, questioned the methodology used to determine whether attackers are left- or right-wing.
"It can be very messy" with people who have conflicting ideologies, he said while noting that the findings made sense.
"It's touching on something real," Holt said.
"I don't think it's wrong to say left-wing attacks have seemed to occur at a more frequent pace, but the previous pace was extremely minimal," he said, adding that right-wing violence is still a threat.
"These trends can reverse on the flip of a dime," he said, and they're "a symptom of the same thing. It's an extremist world view."
As for how to combat the problem, the report said U.S. political leaders and activists "need to lead by condemning violence on their side and calling for calm when it involves violence on the other side."
Both Trump and Vice President JD Vance have blamed the left for political violence in the aftermath of the Kirk shooting.
"If you look at the political violence in our country over the last couple of months, the last couple of years, it is not a both sides' problem. It is primarily on one side of the political aisle," Vance told reporters in North Carolina on Wednesday.
Vance and other Republicans have cited recent polling from YouGov showing that, while majorities in all groups opposed political violence, larger shares of younger and liberal-leaning respondents said that violence "can sometimes be justified" compared to the overall population.
However, there are serious questions about whether public polling on hypothetical questions is accurately measuring feelings about political violence in the U.S., and the CSIS report said it's increasingly common for people on both sides of the political spectrum to think the worst of their political opponents.
"While less than 4 percent of Americans express support for partisan violence such as assault, arson, or murder, both sides greatly overestimate their opponent's willingness to endorse such actions, with Democrats believing 45.5 percent of Republicans support partisan murder, and Republicans believing that 42 percent of Democrats do," the report said.
Those perceptions, the report said, create "a dangerous environment where extremists can more easily rationalize using violence."