Beck’s version of American history relies on lessons from his own acknowledged inspiration, the late right-wing writer W. Cleon Skousen, and also restates charges made by the Birch Society’s founder, Robert Welch. The political universe is, of course, very different today from what it was during the Cold War. Yet the Birchers’ politics and their view of American history—which focussed more on totalitarian threats at home than on those posed by the Soviet Union and Communist China—has proved remarkably persistent. The pressing historical question is how extremist ideas held at bay for decades inside the Republican Party have exploded anew—and why, this time, Party leaders have done virtually nothing to challenge those ideas, and a great deal to abet them. . . .