To be sure, mass attackers today have a new set of coded phrases, such as “replacement,” as a code for racial annihilation through intermarriage, immigration and demographic change. But the idea of that threat has been central to white power activism for decades.

To people in this movement, the impending demographic change understood by many commentators as a soft transformation — the moment when a town, a county, or a nation will no longer be majority-white — isn’t soft at all, but rather represents an apocalyptic threat.

In a decade of studying white power movement activism, I have learned that much of this follows a strategy. First, it claims a state of emergency and gives a rationale for the act of violence.

But critically, it also issues a call to action for others. The El Paso manifesto does so overtly, and offers tactical details about the attacker’s weapons, meant to instruct others. It has specific advice about how to choose targets. It has paragraphs that give rote gesture to not being white supremacist, even as the document invokes phrase after phrase, ideological marker after ideological marker, of the white power movement. These are all markers of the genre.

As horrible as the El Paso attack was, this movement is capable of even larger-scale violence. The Oklahoma City bombing, its most horrific act to date, was the largest mass murder on American soil between Pearl Harbor and 9/11. Not only do we still lack a widespread understanding of that bombing as an act of political violence, but we fail to reckon with the many activists that create shrines to Timothy McVeigh and hope to follow in his footsteps.

The history of the white power movement shows us that what seems new in El Paso is not new at all. This movement is not newly dangerous because of social media; it has been using the internet and its precursors in precisely this way since 1984.