These jarring, tragic events have cast new attention on the rise of extremist behavior in the United States. Researchers and law enforcement officials say the issue has been neglected, allowed to fester and proliferate. Stoked by divisive rhetoric on cable news, social media, and online message boards, domestic terrorism is an expanding national security threat, and while white supremacist violence has been the most prevalent, extremism is growing in all corners and ideologies.

As far back as 2009 analysts at the Department of Homeland Security warned of the rising threat of domestic terrorism, particularly from white supremicist factions. At the time, the report got caught in the political spin cycle, dismissed as partisan fare that demonized conservative views, and the team that produced it was reassigned. Today, agents investigating foreign terrorism still wield far more resources and legal power than those pursuing threats at home.

“On the left and the right there is denial about the extent that this is happening,” said David Neiwert, a reporter who has covered white nationalists for decades and the author of Alt-America: Rise of the Radical Right in the Age of Trump. “It’s such an ugly thing, nobody wants to acknowledge these things are going on in America.”

Hate, extremist violence spread

In 1995, 168 people were killed in the bombing of the Oklahoma federal building, and Google was still three years from existence. Today, domestic terrorists are proliferating online, according to law enforcement officials, coordinating, planning, and drawing inspiration from one another through digital postings and manifestos.

Anders Breivik, the Norwegian who killed 77 people in a 2012 mass shooting and bomb attack, influenced the man who attacked two mosques on March 15, 2019, in Christchurch, New Zealand, Neiwert said. He, in turn, appears to have influenced the El Paso shooter.

Several of the manifestos, including that of the New Zealand shooter entitled “The Great Replacement,” drew on theories promoted by French writer Renaud Camus, who claims European elites wish to replace white Europeans with immigrants from the Middle East and North Africa.

As violent crime rates nudged slightly downward from 2010 to 2017, FBI-reported hate crimes climbed more than 8%, according to an analysis by the Center for the Study of Hate and Extremism led by director Brian Levin. In May, the head of the FBI’s counterterrorism division said the bureau was investigating 850 domestic terrorism cases, 40% driven by racist motivations.

FBI Director Christopher Wray said at a July House hearing white supremacy presents a “persistent” and “pervasive” threat to the United States.

The El Paso shooter, who drove 10 hours across Texas to a Walmart where he shot and killed 22 people, has been connected to a manifesto dripping with racism and hatred posted to 8chan, the online community popular with radical right extremists. The unsigned document, titled “The Inconvenient Truth,” bluntly states: “This attack is a response to the Hispanic invasion of Texas.”

The gunman who opened fire at a synagogue in Poway, Calif., in April posted an anti-Semitic rant on 8chan before killing one and wounding three others. The man accused of killing 11 people at a Pittsburgh synagogue in October 2018 derided immigrants, Jews and other groups online.

“After an event like El Paso takes place the talk on sites like the Daily Stormer, Gab, 8chan etc. is downright celebratory,” Neiwert said. “They have this competition going where they are scoring each event, and basically your body count is how you score points. They are gamifying mass killing.”

The Poway shooter was “mocked for having a low body count,” Neiwert added.

Deluge of divisive rhetoric

On Aug. 3, the same day as the El Paso shooting, a man at a Montana county fair choked and body slammed a 13-year-old boy, fracturing his skull, allegedly because the boy didn’t remove his hat during the national anthem.

“His commander in chief is telling people that if they kneel, they should be fired, or if they burn a flag, they should be punished,” the man’s attorney told the Missoulian. “He certainly didn’t understand it was a crime.”

While extremist organizations and messaging have existed for decades, Trump’s ascendancy to the White House coupled with easy access to extremist messages and community building on the internet have emboldened people to express and act out radical views, analysts argue.

“This is not just going to pass,” Neiwert said. “America has to wake up to the reality that we have 24/7 cable channels that coach half of America how to hate the other half.”

Hate crimes spiked around Trump’s November 2016 victory, according to a study by Levin and his colleagues, with 27 reported incidents the day after the election alone. There were 735 reports that month, the worst month since 2007. Between 2016 and 2017, hate crime reports jumped 17%. After seeing Trump’s statements about certain groups, people were more likely to write offensive things, not only about those targeted by the president, but about other groups as well, according to Documenting Hate, a media collaborative, has recorded more than 300 cases of Trump’s name being invoked in hate speech or hate crimes since 2017. Trump’s eliminationist rhetoric—when he refers to opponents as vermin or diseases—adds fuel to the violent, extremist factions growing in the United States, Neiwert said.

“It’s granting permission for people to act out any way they can toward the end of purifying the nation and getting rid of these evil influences,” he said. “A lot of these people wind up being those posting against race mixing like the El Paso shooter was going on about in his manifesto, it was about maintaining the purity of their community.”

Trump and his supporters deny allegations that the president’s rhetoric encourages violence.

“To simply ask the question every time something like this happens overseas, or even domestically, to say, ‘Oh my goodness, it must somehow be the President’s fault,’ speaks to a politicization of everything that I think is undermining sort of the institutions that we have in the country today,” acting White House Chief of Staff Mick Mulvaney said after the New Zealand attacks.

Growing threat met by unfocused response

Now, experts are concerned not just about far left or right terrorism but about new extremists who favor violence and destruction above all else, unbound by traditional political ideologies.

“While white supremacists and ultra-nationalists will maintain their position at the top of the threat matrix,” Levin wrote in a July 2019 report on U.S. hate crimes and extremism, “the risk is also diversifying” to include people with “antagonistic ideologies, those inspired by zealots and conflicts abroad, and those with more personal grievances.”

Neiwert is following a spike in “accelerationism,” people who believe democracy has failed and have a “let’s blow it all up” mentality reminiscent of Tyler Durden in “Fight Club.”

“They want the system to come down—to destroy the system,” he said. “… They don’t fall on the right or left side of the spectrum, they are just misanthropes ultimately.”

One of the former analysts behind the dismissed 2009 DHS report is still sounding the alarm. In June, Daryl Johnson published “Hateland,” a book chronicling the recent rise of U.S. domestic terrorism and radicalization. He recently told The Guardian he sees the issue “getting worse,” and not “going away anytime soon” without more resources and focus from government. 

Still, while the three recent mass shootings are being investigated as domestic terror attacks, there is no criminal charge behind the label, and no U.S. agency has the task of officially identifying domestic terrorism organizations.

In an August 6 Washington Post Op-Ed, retired four-star Marine Corps General John R. Allen and national security expert Brett McGurk—both former special presidential envoys for the Global Coalition to Counter ISIS—called “domestic and homegrown white nationalist terrorism” the “new national security threat.” 

“It is terrorism directed at innocent American civilians,” they wrote. “If the Islamic State or al-Qaeda were committing such acts, the nation would mobilize as one to overcome it.”

More must-read stories from Fortune:

—Why the U.S. labeled China a currency manipulator

—How Trump’s plan to import Canadian drugs would work

—What you need to know about 8chan, the controversial site tied to the El Paso shooting

—After the El Paso shooting, a call for stronger protections for Mexicans in America

—Listen to our audio briefing, Fortune 500 Daily

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