Ronald Reagan was angry. It was October 1986, and his veto against the Comprehensive Anti-Apartheid Act had just been overridden — and by a Republican-controlled Senate, at that.

He had appeared on TV a month earlier to warn Americans against the Anti-Apartheid Act, decrying it as "immoral" and "utterly repugnant." Congress disagreed, and one month later, it produced the two-thirds majority needed to override Reagan and pass tough new measures against South Africa's apartheid government. These measures included a ban on bank loans and new investments in South Africa, a sharp reduction of imports, and prevented most South African officials from traveling to the United States. The Act also called for the repeal of apartheid laws and the release of political prisoners like African National Congress (ANC) leader Nelson Mandela, who had spent the last 23 years in prison.

It is difficult to fully comprehend the evils of apartheid today. Blacks were denied citizenship and the right to vote. They were forcibly relocated into impoverished reservations. People of color were barred from operating businesses or owning land inside white areas, which comprised most of the country. Sexual relations or marriage between people of color and whites was strictly forbidden. Racial segregation was enforced in public areas, including schools, hospitals, trains, beaches, bridges, churches and theaters. To enforce apartheid, the government often resorted to police brutality, the imprisonment and assassination of political dissidents, and the murder of black protesters.

The United States had a complicated relationship with South Africa. Hawks in the U.S. national security complex had argued since 1948 that South Africa was an important ally in the fight against communism. Their arguments persuaded presidents from Truman to Nixon to stifle criticisms of apartheid in the interest of maintaining good relations with the white South African government, whose leaders surpassed Joseph McCarthy in their anticommunist zeal....