After Charlie Kirk’s killing, an expert in political violence explains how to stop it

By Matt Field | September 17, 2025

Attendees flee after Charlie Kirk was shot at a college event in Utah. Credit: Trent Nelson/The Salt Lake Tribune/Getty Images.Share

Robert Pape, a professor at the University of Chicago, has been studying political violence for 30 years. He says he’s advised every White House since 9/11 as well as the US military on various topics, including, for example, how to respond to the Bosnian civil war in the 1990s. That’s all to say Pape has firm ideas about what causes political tensions to boil over. There’s one central factor, he says, that is responsible for the increasingly violent tenor of US politics, most recently evidenced by right-wing activist Charlie Kirk’s on-stage assassination: massive demographic change. Since 1990, the United States has gone from being about 76 percent white to 58 percent white, and in 15 years, give or take, Pape says, whites will be in the minority.

Such demographic shifts can change the trajectories of political parties. It’s even possible that they have destabilized governments for centuries, playing a role in civil wars, revolutions, or rebellions throughout history. As Columbia University sociology professor Yao Lu puts it, tension over immigration has exacerbated political polarization in the United States and elsewhere, “giving rise to surging nativism and a democratic decline.” The arrival of newcomers can lead to a backlash against a supposed economic and cultural threat. (Think of the rise in the fortunes of the KKK in the 1920s or the era’s notorious Palmer raids to clamp down on dissent—which came on the heels of a decades-long massive surge in immigration to the United States.)

“That’s why immigration became Trump’s number one issue almost overnight,” Pape says.

But while the population shift in the country “is the big, big thing that’s radicalizing our politics,” Pape thinks that there’s something else that will need to be dealt with first—highlighted by the aftermath of Kirk’s murder.

Left to its own, Pape says, the emotion created by startling acts of political violence—such as terrorist attacks, for example—can grow and push a society in previously unimaginable directions, a cycle that has happened in other times or other countries.

The Kirk assassination “was done politically to wound a community,” Pape says. When a community faces a terrorist attack or political violence, “what you see is that they have initial emotions of sorrow and fear that morph into anger—and that can morph into very large support for political violence.”

To redirect the growing emotions around Kirk away from violence—Pape notes that the podcaster and activist has won millions of new fans in recent days—Pape wants political leaders, to hold a summit. In particular, he names President Donald Trump and two of his leading Democratic antagonists—governors Gavin Newsom of California and JB Pritzker of Illinois—as being key figures to get on board with any such summit.

“You’re not only trying to take the temperature down from your own side, but you’re showing you’re willing to live together,” Pape says.

Support for political violence, on the other hand, only begets more political violence. It creates a “mantle of legitimacy for volatile actors that can push them over the edge,” Pape says. “When you have that large amount of public support, that creates an additional perception that they’re doing a community good. And that is what can nudge people over the edge.”

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Kirk’s shooting is just one of many recent examples of concerning political violence in the United States. Earlier this summer, a man killed Democratic Minnesota State representative Melissa Hortman and her husband after shooting and injuring another Democratic lawmaker and his wife.  A gunman who allegedly had become convinced that the COVID vaccine had made him sick—an idea that is prominent in some right-wing circles—shot at the Centers for Disease Control and Prevention (CDC) headquarters in August. An arsonist upset over the Israel-Palestine conflict lit a fire at Democratic Pennsylvania Gov. Josh Shapiro’s residence in April. A man broke into former House Speaker Nancy Pelosi’s house and beat her husband with hammer in 2022. There were two apparent attempts to kill Trump during the 2024 presidential election, including at a Pennsylvania rally where Trump was wounded.

According to Pape’s surveys, significant numbers of people support political violence. When the Chicago Project on Security & Threats, which Pape directs, conducted a poll in May on the topic, about 39 percent of Democrats, for example, supported the use of force to remove Trump from office while 24 percent of Republicans supported a military intervention to suppress protests against the “Trump agenda.”

The difference between the two numbers can be overstated, because the poll asked different questions to elicit the Democratic and Republican responses, Pape says. But in general, he feels that in the 1960s, the left was responsible a lot of the time for political violence; afterword, there were a few decades when the right and militia groups were more likely to take this approach, Pape says. He calls trying to find out which political faction is more responsible for political violence “a fool’s errand.”

Most people don’t support political violence—some 70 percent, according to Pape’s research. A lot of thinking around suppressing terrorism or political violence, Pape says, has focused on going after extremists.

“There is another approach, which is not at odds with the first one, but it is a force multiplier,” he says. “Lean into the 70 percent who abhor political violence, have them do more of the work.”

Having leaders reflect that 70 percent, Pape says, can help shrink the space for political violence on the political wings.

Pape has seen some promising signs, he says, pointing out an appearance by a Republican and a Democratic senator on CBS’s Face the Nation on Sunday as well as a segment on the same show that featured House Speaker Mike Johnson, a Republican, who called for political leaders to “turn down the rhetoric.”

Pape, meanwhile, is grading Trump’s response to the Kirk killing on a curve. Trump, after all, seems to love channeling anger and has advocated for violence against his political opponents.

Days before the Kirk assassination, Pape notes, Trump alluded to invading Chicago, posting an image of himself in fatigues in front of the city skyline, with helicopters flying by and flames shooting up from behind. “Chicago about to find out why it’s called the Department of War,” Trump wrote at the time.

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After Kirk died, Trump last week released a video praising the activist as a “patriot who devoted his life to the cause of open debate” before blaming the radical left “for the terrorism that we’re seeing in the country today.”

Perhaps it could have been worse.

“It is important to see that if you compare it to just what happened the previous Saturday with his ‘Chi-pocalypse” posting, I do think he may well have thought he had taken the temperature down some,” Pape says of Trump’s Thursday video on Kirk.

“He really needs to do more, should do more to restrain his own side, to restrain the Republican side and the reaction to the Kirk assassination,” Pape says.

The next day, after 22-year-old Tyler Robinson, was arrested, Trump had totally dispatched with any attempt at a measured response and called leftwing radicals “vicious” and “horrible.”

“He said in that interview that the radicals on the right were essentially justified—the problem was only the radicals on the left,” Pape says. “And that is going to make matters worse.”

People close to Robinson—his father and his romantic partner, for example—have reportedly been helping law enforcement with the case.  And he is believed to have acted alone. Nevertheless, the Trump administration in recent days has been previewing a wide crackdown of groups on the left, holding a potentially large swath of people or organizations responsible for the killing.

The president has said he wants to designate unspecified groups as domestic terrorists and deploy so-called RICO cases against protest funders, citing a law commonly used against organized crime groups, the Racketeering Influenced and Corrupt Organizations Act. Vice President JD Vance guest-hosted an episode of Kirk’s podcast in which administration officials pledged to use, according to The New York Times, “every available lever of the federal government” to crack down on leftist nongovernmental organizations.

On the left, meanwhile, many have dissected Kirk’s many racist and hateful statements in online posts that sometimes seem to imply that Kirk was rhetorically responsible for his own murder. Some moderates have found themselves attacked for supposedly white-washing Kirk; former President Barack Obama was vilified among some for releasing a statement decrying political violence after Kirk was killed. In a similar vein, New York Times columnist Ezra Klein has come under heavy criticism for writing a column lauding Kirk for his spirt of political debate. The Bluesky social platform is awash with jokes and criticisms about Klein’s supposedly tepid moderation.

Pape believes the country is in a dire situation that could soon become even more so. “We’ve had all this whole spate of political violence already,” he says. “We were already in the heart and the grasp of what I call the era of violent populism before this.” The coming mid-term elections, which will likely be viewed as incredibly consequential, will only make it harder to slow down any growth in support for political violence.

“We got to have a real off-ramp.” Pape says. “Now is the time to do it. I’m not saying that we’ll stop trying to come up with off-ramps later, but now’s a pretty good time.”

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