This notion — that America is not simply another nation-state but an “idea” — is itself the big American idea, the “beating heart” of what’s known as American exceptionalism. It’s what allows Americans to label certain things un-American even when those things have existed for centuries within the territorial boundaries of the United States. “America is capable of being un-American,” lamented Richard Cahan, one of the authors of a recent book on Japanese internment — a seemingly absurd claim but, within the exceptionalist tradition, an entirely plausible one.
Americans have been denouncing each other in this manner almost since the dawn of the republic. By the early 20th century, the accusation encompassed a vast and incoherent range of political convictions. “Americans are very fond of classing as un-American anything they don’t like,” The St. Louis Post-Dispatch complained in 1909, ticking off tariffs and trusts, prohibition and social drinking, boycotts and “the intimidation of workingmen” as just a few of the positions declared “un-American” by their opponents.
Beverly Gage, “Second Nature”, The New York Times Magazine (26 March 2017), 12.