Fox News Channel host Tucker Carlson successfully injected a longstanding “white genocide” conspiracy theory about land reform measures in South Africa into President Donald Trump’s mind, rendering his primetime “Tucker Carlson Tonight” show a conduit for racist conspiracy theories advanced by the most radical white supremacists in the world for delivery to the Oval Office. White nationalists, expressing their enthusiasm online, are thrilled.

Last night, Carlson fired up a segment that presented as fact the racist tropes of years-old “white genocide” conspiracy theories surrounding land reform measures in South Africa. The measures were enacted in the post-apartheid era as a gradual way of addressing the economic disparity left in the country between black South Africans and the white Europeans who colonized the resource-rich land, stealing land from non-white citizens and forcing non-white people into “homelands” that held 70 percent of the population in 13 percent of the country. To meet land-reform goals set out by the African National Congress after the fall of apartheid, South Africa President Cyril Ramaphosa has proposed an amendment to his country’s constitution that would allow for the expropriation of land for redistribution. As of December 2016, according to an audit by the South African magazine Landbouweekblad and Agri SA, white South Africans have possession of 73 percent of the nation’s agricultural land.

Now that the South African government is working to slowly undo the racial wealth disparity created by white rule and apartheid, extremist groups in the region have teamed up with the international far right, and in some cases unabashed violent neo-Nazis, to spread a false narrative long advanced by white supremacists that the South African government is enacting “anti-white” racism and provoking violence upon white people akin to the early stages of a genocide, despite the fact that genocide watch groups have vehemently rebutted that assertion. Carlson’s show has long been acknowledged as a favorite of white nationalists and a hotbed of American racism.

The president took notice of the segment, tweeting last night that he was directing Secretary of State Mike Pompeo to investigate Carlson’s assertion that land would be taken from white farmers because they “have the wrong skin color.”

I have asked Secretary of State @SecPompeo to closely study the South Africa land and farm seizures and expropriations and the large scale killing of farmers. “South African Government is now seizing land from white farmers.” @TuckerCarlson @FoxNews — Donald J. Trump (@realDonaldTrump) August 23, 2018

The South African government responded with a tweet saying that it “totally rejects this narrow perception which only seeks to divide our nation and reminds us of our colonial past.”

South Africa totally rejects this narrow perception which only seeks to divide our nation and reminds us of our colonial past. #landexpropriation @realDonaldTrump @PresidencyZA — South African Government (@GovernmentZA) August 23, 2018

The Anti-Defamation League released a statement expressing concern that Trump’s tweet announcing Pompeo’s investigation “echoed a longstanding and false white supremacist claim that South Africa’s white farmers are targets of large-scale, racially-motivated killings by South Africa’s black majority.” Dylann Roof, a white supremacist who murdered nine people in a predominantly black church, mentioned South Africa’s supposed “white genocide” in his manifesto and wore patches depicting South Africa’s apartheid-era flag.

This development follows a week in which white nationalists were revealed as being close to White House officials. Earlier this week, a speechwriter for the president was fired when CNN’s KFile investigative team revealed he had spoken at the 2016 H.L. Mencken Club Conference, a favorite of white nationalist Richard Spencer, and appeared on a panel with white identitarian author and editor Peter Brimelow. Days later, it was reported that Brimelow, who runs the white nationalist site VDare.com, had appeared as an invited guest at a birthday party for Trump’s National Economic Council director Larry Kudlow, which took place at Kudlow’s Connecticut home.

Groups responsible for the international propaganda campaign advanced by Carlson on his show—and which Trump has now made foreign policy—are, most prominently, the Afrikaner rights group, AfriForum, and the radical Afrikaner white survivalist group, Suidlanders.

AfriForum, which has campaigned against “expropriation without compensation,” has met with the office of Republican Sen. Ted Cruz of Texas, taken photos with Trump’s National Security Adviser John Bolton, and spoken with officials at the Cato Institute and Heritage Foundation. Earlier this year, AfriForum spokesperson Ernst Roets appeared on Carlson’s show. He has also appeared alongside the incredibly popular far-right YouTuber Stefan Molyneux.

Suidlanders, which describes itself as an “emergency plan initiative” for a “coming violent revolution,” is an organization that has worked with countless white supremacists to prepare for what they believe to be an impending black-versus-white race war. The group has been bolstered by such alt-right platforms as “The Daily Shoah”—which is a reference to the Holocaust—and the white nationalist web-radio outlet Red Ice, in addition to the likes of Mike Cernovich and hosts at the conspiracy theory outlet Infowars. Suidlanders spokesperson Simon Roche, who is often featured in these interviews, has deep ties to white supremacist groups and has addressed the white nationalist group American Renaissance, and called into a podcast hosted by violent neo-Nazi Christopher Cantwell. In South Africa, Suidlanders has taken credit for an increase in global chatter about “white genocide.”

Earlier this year, South Africa became the “flavor of the month” of the online far right, according to far-right figure Faith Goldy. Rebel Media’s Katie Hopkins and alt-right YouTuber personality Lauren Southern traveled to the country and paired with AfriForum and Suidlanders to produce documentary videos that set out to expose a puported “ethnic cleansing” targeting white farm-owners. The “Farmlands” documentary that Southern eventually rolled out highlighted unabashed extremists, including Dan Roodt, a former official of the white separatist National Front group in South Africa, and put forward the example of a whites-only town she visited as a possible solution to the woes that the far right believes immigration has inflicted upon the Western world.

Michael Bueckert, a graduate student and contributor at the website Africa is a Country, who has intensively studied the far-right South Africa propaganda effort, told Right Wing Watch, “Trump’s tweet is the direct result of the work of South African white nationalists who have been pushing the international alt right to adopt this ‘white genocide in South Africa’ narrative, which is based in factual errors, blatant misrepresentations, and is motivated by fundamentally racist logic.

“Over the past two years, but particularly in the first half of 2018, alt-right media [and] think tanks—including the CATO Institute and Fox News—have freely given a platform to a fringe group of South African white nationalists who have successfully hijacked and shaped the international response to land reform efforts in South Africa (which are necessary and overdue),” Buecker said.

Naturally, Trump’s tweet thrilled white nationalists from both the old and new guard of hate, who cheered as their “white genocide” conspiracy theory was thrust into the American mainstream.

Lauren Rose, an alt-right YouTuber who identifies as an “ethno-nationalist,” celebrated Trump’s tweet.

David Duke, the former KKK Grand Wizard and GOP politician, thanked Trump.

White identitarian group Identity Evropa, which has successfully recruited troves of college-age students into the hate movement, was also thrilled.

Southern, having played a large role in bringing the propaganda to American audiences, wrote, “This is huge.”

Red Ice TV, the video-offshoot of the web-based white nationalist radio station Red Ice, proclaimed, “Wonderful!”

Infowars host Jake Lloyd, who wouldn’t tell us whether he knew he was hosting white nationalists on Infowars, thanked Southern, Carlson and Trump, for the tweet.

White nationalist podcaster Nicholas Fuentes was jubilant. He also sniped at HuffPost reporter Christopher Mathias, tweeting that white identity “is entering the mainstream and there’s literally nothing you can do about it, demon.”

Jason Kessler, who organized Unite the Right, which drew a small crowd of neo-Nazis earlier this month, retweeted a post celebrating that “Trump finally mentioned white people by name.”

Gab, the alt-right alternative to Twitter, was flooded with celebratory messages.

I don’t even have to tell you what Gab is like right now pic.twitter.com/8LQmnmuj3J — Jared Holt (@jaredlholt) August 23, 2018

Scott Greer, one of the many Daily Caller authors with ties to white nationalists, wrote: “God bless Donald Trump.”

Hunter Wallace, of the white nationalist publishing house Occidental Dissent, praised the Trump tweet and wondered whether it was “4D Chess.”

Mike Peinovich, who hosts the “Daily Shoah” white nationalist podcast, said Trump’s tweet was “how we slowly chip away at the all-consuming anti-white discourse.”

Among the far-right in South Africa, there’s a similar celebration happening right now, Bueckert tells us.

“There is widespread jubilation among far-right white South Africans this morning because they correctly recognize that Trump is effectively mainstreaming their conspiracy theories, and giving them serious momentum and legitimacy, which they sorely lack in South Africa itself,” Bueckert said.