In 1975 he was appointed ambassador to the United States while also serving as permanent representative to the United Nations.
As foreign minister, Mr. Botha was involved in the talks that led to Zimbabwe’s independence in 1980, and talks that preceded Namibia’s independence a decade later. He negotiated a delicate peace accord between South Africa and Mozambique in 1984.
Mr. Botha also helped broker an agreement that brought an end to a Cold War proxy struggle in Angola, which included South African forces on one side and Cuban troops on the other.
In addition to his son Piet, Mr. Botha’s survivors include his wife, Ina; another son, Roelof; two daughters, Anna Hertzog and Lien Botha; and a number of grandchildren and great-grandchildren. His first wife, Helena Bosman, died in 1996.
Toward the end of his life, Mr. Botha paid tribute to Nelson Mandela and the goal of racial coexistence.
“From our point of view, he led an organization which we regarded as a terrorist organization, and they saw themselves as freedom fighters,” he said in an interview with the BBC in 2013, the year Mr. Mandela died. “Of course, all of that had to change. It is not always that simple and easy to change, you know, mental attitudes, mind-sets, but eventually it did change.”
Speaking of Mr. Mandela, he said, “I so often experience his capacity to forgive, and then his will to improve the country, its systems, the poor black people, uplift them but without damaging the economy.”
He added, “Black and white in this country need each other to succeed.”