When the University of Massachusetts decided in 2008 to rescind the honorary degree it had awarded Robert Mugabe 22 years earlier, it noted that Zimbabwe’s dictator had once been seen “as a force for democracy and reform.” Even then the self-deception was breathtaking.

Not long after ending white rule and coming to power, Mugabe — who may (or may not) have been gently deposed from power this week in a soft coup — unleashed a war of atrocity against his ethnic rivals in the Ndebele tribe, promising that he would pursue his enemies “until all dissidents are eliminated,” according to a 1983 report by Alan Cowell in The Times.

“The soldiers came to our village,” Cowell reported that one elderly Ndebele woman said. “They burned our huts and called for the young men who had left the army. Then they killed 15 of them.”

The scale of Mugabe’s killing, estimated as high as 20,000, might not have been known to the good people of Amherst in 1986: Mass graves would continue to be unearthed for years afterward. But there was no mystery about his methods. The real mystery is why Western liberals and progressives so often fall for the Mugabes of the world, and why they seem to learn so little from successive and inevitable disenchantments.