A racist ideology is being investigated as a motivating factor behind a “racist” shooting at a Buffalo supermarket that left 10 dead.
The shooter was white and most of the victims of were black.
A reported 180-page racist diatribe posted online by the suspected gunman that included specific plans to attack black people surfaced online shortly before the attack, frequently citing “the Great Replacement” theory.
While authorities are working to confirm the document's authenticity, they described the attack as “racially motivated violent extremism”.
What is the 'Great Replacement' theory?
The conspiracy theory essentially says that non-white people are being brought into the US to “replace” white people.
“The Great Replacement” also occasionally includes baseless assumptions that non-white immigrants will vote a particular way, “and therefore pro-immigration policies are designed by elites to diminish the political influence of white Americans”, the National Immigration Forum said.
The document also claims that “critical race theory” is part of a Jewish plot and uses this to justify the mass killing of Jews.
White nationalists marching at a rally in Charlottesville, Virginia, in 2017 that ultimately turned deadly chanted “You will not replace us!” and “Jews will not replace us!”
The white supremacist gunman who killed 51 people at a Christchurch, New Zealand, mosque in 2019 was cited by the suspected Buffalo gunman in the document.
White supremacists have cited the conspiracy in other deadly attacks, including the 2018 Tree of Life Synagogue in Pittsburgh, Pennsylvania; in an El Paso, Texas, Walmart in 2019; a black church in Charleston, South Carolina in 2015; and a California synagogue in 2019.
What is its origins?
The conspiracy's roots date back to French nationalism books published in the early 20th century, the Anti-Defamation League said.
In the modern era, most experts point to two influential books: The Turner Diaries, a 1978 novel written by William Luther Pierce under the pseudonym Andrew Macdonald, is about a violent race war in the US that leads to the extermination of non-whites.
French writer and critic Renaud Camus published an essay titled Le Grand Remplacement, which claimed Europe was being invaded by African immigrants, which would result in the extinction of the white race. Camus focused on Muslim and non-white Europeans as they had higher birth rates, the ADL said.
Who is propagating the theory today?
Tucker Carlson, Fox News’s most popular personality, has pushed false views that are more easily embraced by some white people concerned about the loss of political and social power.
“I know that the left and all the gatekeepers on Twitter become literally hysterical if you use the term ‘replacement’, if you suggest 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,” he said on his show last year.
“But they become hysterical because that’s what’s happening, actually, let’s just say it — that’s true.”
Fox News defended the host, pointing to repeated statements that Carlson has made denouncing political violence of all kinds.
The attention paid by many Republican politicians to what they see as the leaky southern US border has been interpreted, at least by some, as a nod to the concern of white people who worry about being “replaced”.
House Republican Conference Chair Elise Stefanik’s campaign committee was criticised last year for an advertisement that said “radical Democrats” were planning a “permanent election insurrection” by granting amnesty to undocumented immigrants who would create a permanent liberal majority in Washington.
Ms Stefanik's office rejected that criticism in a statement.
US Representative Liz Cheney, a Republican, called on the party's leaders to denounce white nationalism.
“The House GOP leadership has enabled white nationalism, white supremacy and anti-Semitism. History has taught us that what begins with words ends in far worse,” Ms Cheney said on Twitter.
The Associated Press contributed to this report