An online screed linked to the 18-year-old man arrested for killing 10 people in a Buffalo, New York, supermarket repeatedly referenced the racist and anti-semitic "great replacement theory." 

The theory is white supremacist rhetoric amplified in recent years by some of the loudest voices in conservative media. Several recent shootings have been motivated by belief in a "great replacement," experts say.

The conspiracy theory warns that Democrats and other Western elites are using immigration and other means to "replace" white people of European descent in the U.S. with non-white populations. Some subscribers believe it’s part of an elaborate Jewish plot.

The 180-page document linked to the Buffalo shooter said that he came to believe the white race was in jeopardy after he started browsing 4chan out of boredom at the start of the pandemic. According to the document, which is filled with memes, Payton Gendron chose to attack the people of Buffalo because the city had the highest concentration of Black people among the areas near his home in Conklin, New York.  

The writings mirror postings from earlier attackers who were also inspired by the "great replacement theory," including the shooter who livestreamed his assault on a pair of mosques in Christchurch, New Zealand, in 2019, killing 51 people. 

About 63% of the language in the Buffalo writings was copied from the Christchurch writings, according to the Anti-Defamation League.

The document also invokes the accused shooter who killed 11 people at the Tree of Life synagogue in Pittsburgh in October 2018; the man who pleaded guilty to killing one person at a synagogue in Poway, California, in April 2019; and the man who was charged with killing 23 people at a Walmart in El Paso, Texas, in August 2019. All three signaled support for the great replacement conspiracy theory in online posts, according to the ADL. 

Police walk outside the Tops grocery store on May 15, 2022, in Buffalo, N.Y. (AP)

The concept of a "great replacement" traces back to 20th century French nationalism. But the term was introduced to many contemporary audiences by a French writer who warned in 2011 about the supposed extinction of the white race due to immigrating Muslim populations, according to the ADL. It was quickly taken up by white supremacists, including many who blame Jews for non-white immigration.

The most extreme, violent versions of the theory are found in the darker corners of the internet, such as 4chan and other fringe forums, said Michael Jensen, a senior researcher at the University of Maryland’s National Consortium for the Study of Terrorism and Responses to Terrorism.

But social media, supportive politicians and major media figures have helped the theory’s ideas spread. 

"Replacement doctrine has been circulating for years, but most recently it got a makeover and amplification in mainstream politics," said Brian Levin, director of the Center for the Study of Hate and Extremism at California State University, San Bernardino. 

The central tenets of the theory have become a mainstay on the primetime Fox News show hosted by Tucker Carlson. A recent investigation from the New York Times found that in more than 400 episodes of his show, Carlson "amplified the idea that Democratic politicians and others want to force demographic change through immigration."

Carlson has mocked those who point out his racist rhetoric.

"I know that the left and all the little gatekeepers on Twitter become literally hysterical if you use the term ‘replacement,’ if you suggest that the Democratic Party is trying to replace the current electorate, the voters now casting ballots, with new people, more obedient voters from the Third World," Carlson said in an April 2021 show. "But they become hysterical because that’s what’s happening, actually."

"They’re trying to change the population of the United States, and they hate it when you say that because it’s true, but that’s exactly what they’re doing," Carlson said in May 2021.

A screenshot of a chyron that aired during "Tucker Carlson Tonight" on Fox News on April 12, 2021, accessed via the Internet Archive.

A Fox News spokesperson pointed to other on-air comments Carlson has made denouncing violence but did not offer further comment for this story.

Other right-wing influencers have promoted similar themes, including the late radio host Rush Limbaugh, Daily Wire contributor Matt Walsh and Turning Point USA founder Charlie Kirk.

Kirk defended Carlson’s April 2021 remarks as "factual" and months later claimed, without evidence, that President Joe Biden intentionally let Afghanistan fall to the Taliban as a pretext for admitting more migrants and "chang(ing) the body politic permanently."

Another Fox News personality, host Jeanine Pirro, made a similar comment in 2019 when she said, "Their plot to remake America is to bring in the illegals … to replace American citizens with illegals who will vote for the Democrats."

Rep. Matt Gaetz, R-Fla., also stood up for Carlson, tweeting after Carlson invoked the theory by its name in September 2021 that Carlson was "correct about replacement theory as he explains what is happening to America." That same month, Rep. Elise Stefanik, R-N.Y., said in an ad that Democrats were lodging a "permanent election insurrection" with their immigration policies.

A recent poll from the Associated Press and NORC at the University of Chicago suggested that with a wide swath of Americans, the narrative may be sticking. 

The poll found that one in three American adults now believes "that a group of people is trying to replace native-born Americans with immigrants for electoral gains." The belief was significantly more common among respondents who watch mostly Newsmax, One America News Network or Fox News than among those who watch CNN or MSNBC.

"While Tucker Carlson and other conservative voices do not advocate for violence in response to the ‘great replacement theory,’ their promotion of its central ideas pushes millions of people to the outskirts of the online environments where the most extreme forms of the theory are used to recruit and radicalize people to commit mass casualty crimes," Jensen said.

"It takes only a couple mouse clicks for a curious viewer to get from Tucker Carlson to 4chan."