This paper examines the historical and ideological foundations of replacement theory and its influence on far-right extremist manifestos. It traces the origins of replacement sentiment in the U.S. and Europe, linking it to early 20th-century race science, eugenics, and white supremacist movements. In the U.S., figures like Edward A. Ross and Madison Grant popularized fears of "race suicide," which later evolved into the antisemitic "white genocide" conspiracy embraced by extremists like David Duke and David Lane. In Europe, similar racist narratives emerged from the Nouvelle Droite movement of the 1960s, influencing figures such as Jean Raspail, Oriana Fallaci, and Bat Ye’or, ultimately culminating in Renaud Camus' "Great Replacement" theory.
The paper then analyzes thematic elements in terrorist manifestos inspired by replacement theory, focusing on four key rhetorical themes: (1) the perceived existential threat of non-white immigration, (2) misogyny, (3) the portrayal of demographic change as a global conspiracy, and (4) the concept of a racial holy war (RAHOWA). The study reviews academic literature related to these themes and concludes with a summary of findings on how replacement theory continues to shape extremist ideology.