Just days after a gunman opened fire in a suburban outlet mall in Texas in May, killing eight people, his far-right extremist views became apparent. His online posts and profile, the symbols on the clothing he wore and even his tattoos revealed white-supremacist, neo-Nazi and misogynistic incel ties. While these views are shocking, the fact that the shooting was committed by someone who held them was not. Data on mass killings in the U.S. shows a growing share of violent attacks, as well as attempted or planned attacks, have ties to extremism.
Between 2006 and 2009, fewer than 1 percent of mass-casualty events — intentional, violent attacks where four or more victims are killed within a 24-hour period — had a link to extremism. Between 2018 and 2021, more than 5 percent did, according to a FiveThirtyEight analysis of two databases from the University of Maryland’s National Consortium for the Study of Terrorism and Responses to Terrorism and a collaboration between USA Today, The Associated Press and Northeastern University.1 This data is supported by reports from the FBI, the Department of Homeland Security and the Anti-Defamation League, all of which show a marked increase in violent attacks linked to extremism in recent years.
Most of these extremist-linked attacks are from far-right extremists, and the vast majority of deaths are caused by shootings. Yet when we talk about gun violence in the U.S., far-right extremism is rarely the primary focus of discussion, with mental illness and gun control dominating the conversation. Though a minority of mass-casualty events have an extremist link, those events tend to be more deadly and often have symbolic and political chilling effects that ripple much further than other kinds of mass killings, according to Mark Pitcavage, a senior research fellow at the ADL’s Center on Extremism. “By the very nature of some of these extremist-related mass killings, they’re specifically designed to inspire fear and intimidation and to sway entire populations and governments, which is sort of the definition of terrorism,” Pitcavage said. It’s part of why the FBI has stated violent extremists “pose the most lethal threat to U.S. persons and interests” and why experts say discussions on how to curb gun violence need to include extremism.
Over the last decade and a half, the number of mass-casualty events each year has remained relatively flat. In 2006, for example, there were 38 mass-casualty events in the U.S., resulting in the deaths of 183 people, according to the USA Today/AP/Northeastern database. In 2021, there were 35 events, resulting in the deaths of 172 people; there were also an average of 31 mass-casualty events for each year from 2006 through 2021. Yet despite the total number of mass killings staying static, the number of events with extremist ties has increased, resulting in a higher percentage of extremist-linked mass killings.
There also has been a rise in the number of extremist-linked violent plots, according to the data from START. When extremists consider violent acts, they don’t always result in mass-casualty events. Sometimes perpetrators are caught by law enforcement before any violence can take place; other times fewer than four people are killed, even if the perpetrator likely intended to harm a greater number of people. In April 2019, for example, a right-wing extremist gunman opened fire in a California synagogue, killing one person before his gun reportedly jammed and he fled the scene. It can be hard to know how to analyze these plots, since it’s impossible to predict with certainty what might have happened, but they provide a wider view of the changing landscape of violent extremism in the U.S.
Using criminal charges and other contemporaneous evidence, researchers at START have tracked these extremist-linked violent plots going back to 1990, and the total number has exploded. Between 1990 and 1993, START identified seven extremist plots. Between 2018 and 2021, there were 177 — a 2,400-percent increase.
“Fortunately, most of these plots are not successful,” explained Michael Jensen, a senior researcher at START. Of the more than 400 extremist plots Jensen and his team have identified, just 18 resulted in mass-casualty events, according to FiveThirtyEight’s analysis. “Law enforcement is actually doing a very good job disrupting these things. But what is masked when we don’t talk about that disruption is the actual scale of it, how often these events are being plotted.”
These plots aren't always linked to far-right extremists — far-left, religiously motivated, nationalist and idiosyncratic extremists have all plotted violence in this time period — but in recent years, the majority have been.
Similarly, reports from the DHS and ADL also indicate far-right extremists make up the plurality of violent attacks with extremist ties. Thirty-five percent of domestic terrorist incidents between 2010 and 2021 were classified as “racially or ethnically-motivated,” according to data from the DHS. And a recent report from the ADL found right-wing extremists were behind the majority of extremist-linked mass-casualty events over the past decade.
“Over the past decade, right-wing extremists have committed the majority of extremist-related killings in all years but one — 2016, the year of the shooting spree at the Pulse nightclub in Orlando, Florida, by a person motivated by Islamist extremism,” the report read. “Of the 444 people killed at the hands of extremists over the past 10 years, 335 (or 75%) were killed by right-wing extremists.” The report also found that the majority of deaths caused by these killings are from shootings — over 80 percent of the victims of deadly extremist violence were killed with firearms in each of the last five years.
There are a number of factors that have contributed to the increase in far-right extremist-linked mass killings. The rise of accelerationist white-supremacist ideology in the U.S. — the belief held by some white supremacists that the only way to achieve their goals is through the violent dismantling of society — has been a significant one, according to Pitcavage. The internet has also played a role in radicalizing and connecting a new generation of young men susceptible to extremist ideology, according to Alex Newhouse, a senior research fellow at Middlebury College’s Center on Terrorism, Extremism, and Counterterrorism.
“One of the big [things] that people often do understate is the ability for the internet to basically supercharge social alienation and dislocation, and that is a really big deal when you're talking about mobilizing people to violence,” Newhouse said. “One of the things we know from studies that have been done on this, especially psychological studies, is that those feelings of dislocation from your communities, from your family, from your friends, [are] one of the main psychosocial drivers of radicalization and ultimately violence.”
Newhouse echoed Pitcavage’s point that, while representing a small percentage of total mass-casualty events, extremist-related mass killings are worth paying attention to because of the way they target specific groups, such as racial or ethnic minorities, in order to stoke fear and create chaos.
“There’s an act of intentionality to create more panic to create more political strife, political tension, and extremists choose their targets to maximize that,” Newhouse said. “It is important to recognize that there is a sort of specific threat to ideological violence that doesn't exist in other types, because the targets are deliberately picked.”
As of 10 a.m. Eastern on July 6, there have already been 360 mass shootings (where four or more people were shot, but not necessarily killed) in the U.S. this year, according to the Gun Violence Archive, a nonprofit research group that tracks gun violence. This is a scourge that goes far beyond the handful of extremist-related mass killings that occur each year. But to disregard these events would be to ignore a significant, and growing, deadly threat that has the capacity to stoke fear and division across the country.