In April 1978, an Afghan tank commander rushed to tell President Mohammed Daoud Khan of a coming coup attempt. The President ordered his tank commander to circle to the presidential palace. Khan did not want to be caught off guard. He had only taken the reins of power from the King of Afghanistan five years before and didn't want the monarchists coming back to power.
But when the critical moment to stop the coup came, the tank commander, with tanks surrounding the president, turned his guns on the palace. He was part of the coup all along.
The day after the revolution.
As coup attempts go, it was relatively bloodless, and thankfully short. But this coup would set Afghanistan on a path that would destroy it from within for the next fifty years or more. Daoud Khan and his family were killed in the palace that day, and the Communists under Nur Muhammad Taraki would ascend to the presidency of Afghanistan. Daoud was himself not a member of the Communist party, but the Communists did help him overthrow the monarchy. Once in power, the new president tried to keep Afghanistan non-aligned in the Cold War.
But when you share a border with the Soviet Union, that just doesn't seem likely to happen.
Khan, on the right, shaking hands with senior Afghan military leaders
The problem with being non-aligned is that you can really lean one way or the other. When you ask for favors from a superpower, they expect you to fall in line. So it went for Daoud, who asked for help from the Soviets to settle a border dispute with Pakistan. He struggled to keep the USSR out of Afghan foreign policy thereafter. When a rivalry in the Afghan Communist Party ended with the murder of a faction leader, the Afghans were convinced it was Daoud whose hands were dirty – and that they were next. He didn't have any of them assassinated, but he did have them arrested after protesting the government.
That sealed his fate.
The palace on the day of the coup.
It was on April 27, 1978, that Daoud's trusted tank commander turned on him. He had already defected to the Communist party. By noon, more tanks were rumbling to the palace, the Army occupied important areas of the city, and the Afghan Air Force took to the skies, all against Daoud and his supporters. When the rebels captured the radio station Radio Afghanistan, they announced to the people what was happening.
By the next morning, the President and his family were dead, the palace was lit up like swiss cheese, and the Communists were in control of the country. It turns out Daoud and his brother charged out of the palace toward the army, guns blazing, like a scene out of Butch Cassidy and the Sundance Kid.
Which eventually led to a Soviet invasion.
The reforms implemented by the Communists were mixed, as was the public reaction to the change in power. The new regime was brutally repressive, executed political prisoners, and brutally put down any resistance from the countryside. This repression turned the people against their Communist government, which triggered the Soviet Union's Brezhnev Doctrine – any threat to Communist rule in any Communist government is a threat to all Communism everywhere.
The Soviets invaded and occupied Afghanistan for some nine years. The war was a brutal stalemate that severely set back the development of both countries and may have led to the downfall of the USSR.