The African National Congress (ANC) is Africa’s most famous liberation movement. It has recently celebrated its centenary, a milestone that has prompted partisans to detail a century of unparalleled achievement in the struggle against colonialism and racial discrimination. Critics paint a less flattering portrait of the historical ANC as a communist puppet, a moribund dinosaur, or an elitist political parasite. For such skeptics, the ANC—now in government for two decades—has betrayed South...