Donald Trump made clear on the Philadelphia debate stage this week, as he has throughout his three presidential campaigns, the basis of his run for office. Trump is running on the platform that non-white immigration is an existential threat to the nation. This time around, Trump has made his primary message, the so-called Great Replacement Theory (GRT), more vivid than ever. It is therefore of existential importance in understanding the stakes of this election to have clearly in mind what has happened in the past when GRT has been the central driving narrative both of individuals and of states.

According to the Great Replacement Theory, the nation’s greatness, its traditions and its practitioners, are existentially imperiled by an influx of foreign races, ethnicities or religions. The foreign elements are sometimes described in the narrative of GRT, as vermin or diseases.

GRT was central to the official Nazi motivation for the genocide of the Jews of Europe. Hitler blamed the loss of World War I on Jewish betrayal of Germany. But this betrayal, for Hitler, was intimately connected to the Great Replacement Theory, via the introduction of Black soldiers in the French army subsequently occupying the Rhineland, the so-called “Black Horror on the Rhine.” In Mein Kampf, Hitler writes: