Throughout American history, citizens have been duped. It’s a word as old as the republic itself. George Washington, in his “Farewell Address,” warned about “dupes”—that is, those who, unwittingly, allow themselves to be deceived or misled by active adversaries of the United States.

That process accelerated after the Bolshevik Revolution and into the Cold War, when duping was done on a remarkable scale by crass propagandists in the Communist movement, with America’s liberals/progressives the prime target. Yet, the story does not stop there: Many of the same Americans manipulated during the Cold War have resurfaced in the battle against radical Islam, although the periods, and processes, are quite different.