At the end of the Second World War, the Soviet Union unexpectedly found itself in control of a huge swathe of territory in Eastern Europe. Stalin and his secret police set out to convert a dozen radically different countries to a completely new political and moral system: Communism.

The propagandists share resources—the troll farms that promote one dictator’s propaganda can also be used to promote the propaganda of another—and themes, pounding home the same messages about the weakness of democracy and the evil of America.