When he was governor of California, Ronald Reagan called people from African countries “monkeys” and said they were “still uncomfortable wearing shoes” in a phone call with President Richard Nixon, a recording recently released by the National Archives reveals. Tim Naftali, a history professor at New York University and a past director of the Nixon Presidential Library, writes about the recording for The Atlantic.

As these and other tapes make clear, [Nixon] was a racist: He believed in treating people according to their race, and that race implied fundamental differences in individual human beings. Nixon’s racism matters to us because he allowed his views on race to shape U.S. policies—both foreign and domestic. His policies need to be viewed through that lens.

The 40th president has not left as dramatic a record of his private thoughts. Reagan’s racism appears to be documented only once on the Nixon tapes, and never in his own diaries. His comment on African leaders, however, sheds new light on what lay behind the governor’s passionate defense of the apartheid states of Rhodesia and South Africa later in the 1970s. During his 1976 primary-challenge run against Gerald Ford, Reagan publicly opposed the Ford administration’s rejection of white-minority rule in Rhodesia. “We seem to be embarking on a policy of dictating to the people of southern Africa and running the risk of increased violence and bloodshed,” Reagan said at a rally in Texas.

These new tapes are a stark reminder of the racism that often lay behind the public rhetoric of American presidents. As I write a biography of JFK, I’ve found that this sort of racism did not animate President Kennedy—indeed, early on he took political risks to help African leaders, most notably Gamal Abdel Nasser and Kwame Nkrumah. But his reluctance to do more, sooner for African Americans cannot be separated from the paternalism he brought to the Oval Office or the prejudice held by parts of his Boston inner circle.

Nixon never changed his mind about the supposed inherent inferiority of Africans. At the end of October 1971, he discussed the UN vote with his best friend, Bebe Rebozo. Bebe delighted Nixon by echoing Reagan: “That reaction on television was, it proves how they ought to be still hanging from the trees by their tails.” Nixon laughed.

Remind you of anyone else?