One day after the deadly supermarket shooting in Buffalo, New York, on May 14, it was reported — to absolutely no one’s surprise — that the shooter had published a 180-page document online detailing his plans for the massacre, which targeted a black community and left ten dead. In the document, the shooter outlined the racist ideology that had motivated the attack, with a particular emphasis on the so-called “great replacement” — the white supremacist conspiracy theory that holds that liberal immigration policies and promotion of diversity are part of a sustained conspiracy, usually led by Jews, to flood the country with foreign migrants and “replace” the white majority.

The roots of the great replacement theory, which has motivated white supremacist attacks from Christchurch, New Zealand, to El Paso, Texas, reach back decades — in April 1968, the far-right British politician Enoch Powell delivered his infamous “Rivers of Blood” speech, which warned that “in this country, in fifteen or twenty years’ time, the black man will have the whip hand over the white man” as a result of large-scale immigration and the embrace of multiculturalism. Five years later, in 1973, French author Jean Raspail published The Camp of the Saints, a virulently racist novel in which France and other Western countries are overrun by barbaric, dark-skinned migrants. Looking further back, warnings of “white extinction” and declining “racial hygiene” brought about by immigration and racial intermarriage have featured centrally in the speeches and writings of white supremacists throughout history, from turn-of-the-century eugenicists to Nazi Germany in the 1930s. The great replacement theory as we know it today, however, was first articulated in 2010 and 2011 by French author Renaud Camus, who was deeply influenced by the views of Powell and Raspail and whose writings on the great replacement remain highly influential in far-right and white nationalist circles to this day.

Today, Camus’s rhetoric of replacement has become a staple talking point for far-right media figures like Tucker Carlson, who has explicitly invoked the great replacement on his show. The theory has also gained currency among Republican politicians, from hopeful “new right” candidates like J.D. Vance in Ohio and Blake Masters in Arizona to established politicians like New York congresswoman Elise Stefanik. All of these figures have employed the language of replacement — particularly in the context of immigrants crossing the southern border — as a conspiracy engineered by the Democrats and the “radical left” to promote mass immigration and intentionally alter America’s demographic makeup. The version of the great replacement theory espoused by mainstream Republicans, though certainly no less racist, is generally slightly less extreme than that which circulates on white nationalist 4chan boards, shying away from the explicit language of “white genocide” in favor of more standard GOP talking points about topics such as election security. As a result of this strategic moderation — a moderation of form but not of substance — the great replacement theory has been allowed to implant itself as an established, growing political force on the American right.