The English historian J.A. Froude was famously gloomy about the ultimate prospects for his chosen branch of literature. “To be entirely just in our estimate of other ages is not difficult,” he said. “It is impossible.” Froude’s words came to mind the other day when I encountered Tucker Carlson’s interview with the podcaster Darryl Cooper, whose opinions about World War II may politely be described as “controversial.” No summary could do justice to the parade of oversimplification, decontextualiz...