Critics lambasted the President for endorsing the conspiracy theory to his 54 million Twitter followers. Patrick Gaspard, who served as US ambassador to South Africa under President Barack Obama, noted that this marked the first time Trump mentioned that continent on Twitter since he took office.
"He uses the occasion to lift a white supremacist meme from the darkest place he can find," Gaspard, now president of Open Society Foundations, said. "So many of my friends in South Africa are bewildered that a modern president of the United States, instead of leaning into issues of constitutionalism and jurisprudence, lifts up these themes. It's dangerous and poisoned."
Trump faced an intense backlash for his remarks last summer that a white supremacist rally in Charlottesville, Virginia, where a counterprotester was killed, featured "some very fine people on both sides". In January, he sparked outrage when he complained to lawmakers in a private meeting at the White House that US immigration law offered protections for people from "shithole countries", referring to Haiti, El Salvador and some African nations.
The President's tweet about South Africa marked his latest bid to signal common cause with nationalist movements abroad, including in Europe, where Trump and his top aides have expressed solidarity with populist governments pursuing anti-immigration agendas.
Trump has not visited Africa since taking office, although first lady Melania Trump announced this week that she will visit the continent in October for her first major solo trip.
"President Trump's unfortunate tweet in response to a Fox News broadcast should not distract the United States from improving relations with South Africa," senators Jeff Flake (Republican) and Christopher Coons (Democrat), members of the Senate Foreign Relations Committee, said in a joint statement. "We care deeply about the United States' relationships with all African countries. Constructive relationships require measured dialogue as opposed to arbitrary tweets."
The complicated issue land expropriation has been fraught with emotion in South Africa, whose leaders quickly sought to staunch the enthusiasm of the far-right over Trump's tweet.
Government officials said they would summon US diplomats to explain the Trump Administration's position, although Trump has yet to name an ambassador to the country.
"We would like to discourage those who are using this sensitive and emotive issue of land to divide us as South Africans by distorting our land reform measures to the international community and spreading falsehoods that our 'white farmers' are facing the onslaught from their own government," David Mabuza, South Africa's Deputy President, attending a land summit in Limpopo, said. "This is far from the truth."
Members of Afriforum, the South African white supremacist group, recently toured the US and its causes have been taken up by other white supremacists, including Duke, says Jill Kelly, a South Africa scholar at Southern Methodist University.
She said studies have shown that farm murders are at a 20-year low and murders more generally have been on the decline since the end of apartheid.
Analysts said the conspiracy that white farmers in South Africa were being unfairly treated and attacked in large numbers by nonwhites has persisted for decades. Brian Levin, a professor at California State University San Bernardino who studies hate groups, said the narrative of "white genocide" has been central to the white nationalist movement across the globe.
"Now we have an American leader parroting these talking points once they've been transmitted through cable news. It's astounding," Levin said. "Cumulatively, these messages - and particularly the bluntness and adherence to inaccurate information or conspiracy theories - are taken like rocket fuel within this fragmented, but still very significant, white nationalist community."
In a media briefing in Johannesburg, Julius Malema, the head of South Africa's far-left EFF party, said: "We are more determined, after the Donald Trump tweet, to expropriate our land without compensation ... There's no white genocide here. There is black genocide in the USA."
At the State Department, spokeswoman Heather Nauert confirmed that Trump and Pompeo discussed South Africa and added that Pompeo promised the President he would review the matter of land being taken from white farmers. In general, she said, "expropriation of land without compensation would not be a good thing", and would send South Africa down the "wrong path".
Judd Devermont, director of the Africa programme at the Centre for Strategic and International Studies, said Trump weighing in on the issue was "another example of the president's comments derailing what is still a very unformed and unarticulated Africa policy".
