In October 1977, Civil Rights hero and former Martin Luther King aid Bayard Rustin wrote an 11-page condemnation of Fidel Castro's war in Angola for Commentary magazine, titled "Africa, Soviet Imperialism & the Retreat of American Power." In this brilliant essay, there is a half-sentence that is so innocuous that it is easy to miss: "the Cubans put down a coup attempt in May."

Nothing more is said about this in Rustin's essay, but the event is so significant in Angola that last year, after arresting 13 men for the crime of attending a pro-democracy reading group, Jose Eduardo dos Santos — who is currently in his 37th year as the nation's "President," publicly warned: "It must not be allowed for the Angolan people to suffer another dramatic situation such as the one from May 27, 1977, over a coup d'etat. ... The one who chooses the means of force to take power or uses unconstitutional means for it is no democrat. He is a tyrant or a dictator. They have accused the MPLA and its militants of being intolerant, but lies are short lived."

The Stalinist MPLA party has ruled Angola with an iron-fist since 1975, when Fidel Castro plotted with a departing Portuguese colonial official, a pro-Communist viceroy named Rosa Coutinho, to bring thousands of Cuban military personnel and tons of equipment to the Angolan capital of Luanda. With this assistance, the MPLA seized control. Rosa Coutinho then canceled the election Angola's three independence armies had agreed to — sparking a civil war that left a million Angolans dead and drew the neighboring countries and the superpowers into the conflict. (Coutinho was filmed bragging about this in a 1987 interview, featured in the video below.)

On May 27, 1977, a hard-line black nationalist faction of the MPLA attempted a coup against then MPLA leader and President Agostinho Neto. Thanks to the Cubans, the coup failed and the plotters were executed. But the killing didn't stop there.

What commenced next was a systematic campaign of terror that is the subject of Lara Pawson's book In the Name of the People: Angola's Forgotten Massacre. This book, published in 2014, is the only in-depth study of the rampage launched by the Cubans and MPLA with a speech by Neto declaring "There will be no contemplations ... Certainly we will not waste time with trials. We will be as quick as possible." They were to kill their enemies in the name of the People.

Angolans began to disappear. Not just those suspected of black nationalist sympathies, but their families — as well as anyone who would dissent from the Party. Cuban tanks were brought in to level houses in poor neighborhoods, and one Cuban doctor remembers being brought to witness a mass execution and then handed pre-written death certificates to sign, "In every case, the stated cause of death was acidente de viacao — road accident." A new term entered Angolan vocabulary, "To be sent to Cuba," which could mean literally (as thousands of Angolans were sent there to be brainwashed or trained as killers), but it also became slang for "To be sent to death."

Like Stalin's purges, the death toll of this MPLA purge is unknown. Pawson knows it to be in the tens of thousands. 20,000 is her best estimate. To this day, the words vinte e sete de Maio evoke the same feelings in an Angolan as the words nine-eleven evoke in an American. But it is more than a sense of tragedy because in Angola the official mention of vinte e sete de Maio is a threat powerful enough to halt most dissident activities. And our government doesn't force us to venerate Osama Bin Laden like the Angolan government forces their people to venerate Fidel Castro.

Today's Angola is the fruit of Castro's foreign policy. One million people were killed in the Civil War to keep the MPLA in power. The Party has given Angola both Africa's first and only female billionaire — who, not coincidentally, is the President's daughter — and the highest child mortality rate in the world. "This is a country laden with oil, diamonds, Porsche-driving millionaires and toddlers starving to death," Nicholas Kristof wrote after visiting the country. It is a fitting epitaph to Fidel's legacy beyond Cuba.