John Earnest, accused in the fatal shooting at the Chabad of Poway synagogue, attends his arraignment hearing in San Diego on April 30. (Nelvin C. Cepeda/The San Diego Union-Tribune via Reuters)

Michael Weiss is a senior fellow at the Institute for Strategic Dialogue and co-author of “ISIS: Inside the Army of Terror.” Julia Ebner is a research fellow at the Institute for Strategic Dialogue and author of “The Rage: The Vicious Circle of Islamist and Far-Right Extremism.”

Every wave of terrorism has its intellectual point of departure. For al-Qaeda’s attacks in the West, it was Osama bin Laden’s seminal Declaration of Jihad of 1996; in the case of Islamic State-inspired terrorism, it was the announcement of the Islamic caliphate in 2014. The current wave of white-supremacist terrorism, which recently manifested itself in lethal attacks against mosques in New Zealand and a synagogue near San Diego, can be traced back to a much-less-well-known event.

It was a chilly November day in 2014 when the French writer Renaud Camus addressed an audience of roughly 500 people at a summit organized by the European white-nativist movement Generation Identity in Paris. At this so-called Remigration meeting, Camus warned of the ethnic, cultural and civilizational substitution of the white European people. He blamed what he called (in his eponymous 2012 book) “the Great Replacement” on the actions and policies of the political, media, industrial and intellectual elites.

“The Great Replacement is the most serious crisis that France has witnessed in 15 centuries,” Camus announced grandly in his speech, putting quite the revisionist spin on the Black Plague, Robespierre and Nazi occupation. The gay travel writer turned philosopher of xenophobia has seen his ideas migrate, as it were, across the Atlantic in recent years to lend the pretense of intellectual heft to the alt-right. “You will not replace us,” one of the slogans chanted by white supremacists in Charlottesville in 2017, was a variation on a theme Camus started.

In response to the perceived existential threat of white Europeans being supplanted by nonwhite immigrants, Generation Identity vowed “to work on the diffusion of our concepts among our compatriots and the development of tools for those in power tomorrow.” They’ve been busy ever since. Campaigns to disseminate distorted statistics allegedly proving the Great Replacement started, and the Identitarian concept of “remigration” have accelerated in the past five years, as have calls on social media for the mass deportation of nonwhite Europeans — ethnic cleansing, in essence.

In a forthcoming report by the Institute for Strategic Dialogue, we found that the first spike in social media discussion of the Great Replacement conspiracy theory and the concept of “remigration” coincided with this obscure 2014 meeting in Paris. Since then, our social media analytics tools identified more than a half-million tweets about “remigration” and more than a million tweets referencing the Great Replacement.

One pro-identitarian Twitter account was by far the most prolific in boosting the campaign on social media in its initial stages. It was responsible for more than 10,000 tweets mentioning remigration in the second half of 2015, over 20 times more than the second-most-active account.

Today, these identitarian ideas are much more mainstream — largely thanks to their amplification by far-right politicians, our research shows. Eight out of the 10 most influential accounts for the Twitter discussion around the Great Replacement are French, including several high-profile, far-right politicians. The two non-French accounts on the list are the extreme-right site Defend Europa and, horrifyingly, the president of the United States. (“Influence” was determined by the amount of engagement people received on social media in the context of discussions around Great Replacement-themed keywords over a given period of time.)

Just last week, President Trump retweeted Lauren Southern, an influential proponent of the Great Replacement theory. Hours after the deadly Christchurch shooting, he labeled migrants as invaders, echoing the language the terrorist used in his self-described manifesto. On the day after the Poway attack, Austria’s Vice Chancellor Heinz-Christian Strache said in an interview that he would “continue to pursue the fight against the great replacement.”

Across Europe and the United States, leading politicians borrow the concepts and language of migration-related conspiracy theories, lending legitimacy to the kind of violent extremism once confined to the cultural fringes or obscure corners of the Internet. (Renaud Camus himself is now running for European Parliament — although his list is currently polling at less than 0.5 percent.) In the field of counterterrorism, it has become impossible to ignore the political dimensions of this threat. Heads of state, ministers and political spokespeople now hold a significant share of responsibility for injecting violence-inciting ideologies into today’s zeitgeist.

As the Christchurch and Poway shootings illustrated, the Great Replacement theory finds favor among anti-Muslim and anti-Semitic bigots who have convinced themselves that their pogroms are waged in defense of “civilization.” The fact that two alleged terrorists both referenced the same ideology but chose different targets for their attacks demonstrates only the esoteric difference in enemy prioritization among the far right. While the Christchurch shooting suspect made clear he perceived the Muslim community in the West as the main threat, the Poway shooting suspect said he believed the “global Jewish elites” were deliberately conspiring to change the ethnic makeup of Europe and America. The latter belief was expressed in Charlottesville by the other chant that tiki-torch-wielding white supremacists uttered: “Jews will not replace us.”

To prevent future attacks against Muslims, Jews and other minorities, politicians must go beyond empty condemnations of violent extremism and halfhearted distancing attempts from extremist ideologies. We need to expose any time that politicians’ own words and actions regurgitate outwardly racist beliefs, which, whether by accident or design, give the air of impunity to would-be mass murderers.

Read more:

Rokhaya Diallo: French Islamophobia goes global

The Post’s View: How evil goes viral

Fred Hiatt: Yes, white supremacists are emboldened. But that’s not the whole story in America today.

Max Boot: Not all terrorism is treated equally

Michael Gerson: White supremacy must be undone — institution by institution