Barack Obama still doesn’t understand Donald Trump.

The tweet was largely false. He said he would order the U.S. secretary of state to “study the South Africa land and farm seizures and expropriations and the large scale killing of farmers.” (South Africa is debating the rules for seizing land, not actually seizing it, and there is no large-scale killing of farmers.) Helpfully, Trump provided his source: the Fox News host Tucker Carlson, whose show had just covered the issue.

The Fox host is the link connecting Trump’s statement back to Obama. Earlier this summer, Carlson covered Obama’s speech, tying it to land-reform efforts in South Africa. Ramaphosa’s government is in the midst of a political battle over how aggressively to expunge the legacy of apartheid, which left the ownership of land heavily skewed by the country’s decades-long policy of official white supremacy. His ruling African National Congress (ANC) party has for decades had a policy of redistributing land, but to date has only pursued transactions between willing sellers and buyers. Facing a serious political challenge from the left in upcoming elections, the ANC under Ramaphosa has dropped that policy and is moving to amend the constitution to allow the government to take land without paying for it in certain cases, a policy that’s become known as “expropriation without compensation.” Carlson believes that policy is racist, since it would be used to take land owned by the families that benefited from apartheid, which are, unsurprisingly, white. “Obama knew all this, and he described this as ‘inspiring,’” Carlson said. (Obama did not reference land reform in the speech.)

Since that segment, the lie that Obama supports the theft of white South Africans’ land has become a white-supremacist talking point. YouTube hosts a version of the earlier segment with the description, “Obama In South Africa Praises White Genocide Leaders.” (There is no white genocide, but the idea of it is popular in white-supremacist circles, and the racist Charleston murderer Dylann Roof has aligned himself with the remnants of apartheid.) The hard-right cartoonist Ben Garrison drew a leering Obama standing over Ramaphosa’s shoulder as the South African state steals farmland from tearful whites. (This theft is not occurring, and not pictured are the millions of black families that struggle for access to land.) In the new Fox News segment that Trump referenced, Carlson picked up the talking point again, saying that Obama had praised a racist South African government. Carlson was careful not to explicitly make the false claim that Obama supports land seizures, but the effect is clear. According to Carlson, the U.S. State Department claimed that “President Ramaphosa has pledged that the process will follow the rule of law.” But, Carlson argues, “the State Department did not mention that by following the rule of law, he is changing the constitution to make it possible to steal land from people because they are the wrong skin color.”