Beginning in the 1960s, Castro and Guevara developed a relationship with Angola’s People’s Movement for the Liberation of Angola (MPLA), then locked in an anti-colonial struggle against Portuguese rule. When Portugal’s armed forces staged a mutiny in 1975, a power vacuum ensued. The MPLA was well-positioned to take over, but the National Front for the Liberation of Angola (FNLA) and National Union for the Total Independence of Angola (UNITA) had ideas of their own, forming a fragile alliance. Both would have been utterly uncompetitive, were it not for their foreign backers: Mobutu Sese Seko of Zaïre (the newly renamed Congo-Kinshasa), South Africa’s apartheid government, and the United States. It was an alliance of rare disrepute. In the second half of 1975, tensions between the three Angolan movements became skirmishes, before erupting into open warfare. A minor conflict in a distant African country, ruled for 500 years by a country back in Europe, suddenly came to be seen as a test of wills for different political blocs and their visions for the world’s future.

Each side ratcheted up their contributions in response to the other. Cuba’s contribution soon increased from doctors and technicians to military advisors, infantry, and officers. On the other side of the conflict, South Africa and the United States each saw the MPLA’s rise as a potential triumph for global communism. In August 1975, President Gerald Ford told Secretary of State Henry Kissinger, “I have decided on Angola. … [I]f we do nothing, we will lose Southern Africa.”

Both the United States and South Africa launched separate covert programs to funnel aid and weapons to the FNLA and UNITA, only to find that their rag-tag forces needed much more. Many of the fighters lacked boots and basic military gear. Few had handled sophisticated firearms before, let alone mortars or mines. Though some units had waged guerrilla campaigns against the Portuguese, none had experience in the conventional warfare needed to seize land from the MPLA. The allies realized that a support role would not be enough; they would have to take the lead, deploying regular troops under their own command.

In the wake of the Vietnam War, the U.S. Congress and American public opinion were extremely hostile to another military commitment abroad in a place even more unknown to them than southeast Asia. But elements in the apartheid regime were deeply concerned that an MPLA government in Angola might become a springboard for the African National Congress and for the South West Africa People's Organization, which contested South Africa’s control over South-West Africa (what today is Namibia), through an expired League of Nations mandate. With the white South Africans volunteering a full military effort, the Ford administration decided to let them do America’s dirty work. The South Africans could, and should, have secured an explicit quid pro quo for offering to be America’s shock troops, but failed to do so.