This book is about American popular culture in the age of extremism. “Extremism” is a broad?stroke term that covers a myriad of sins—or virtues—depending on your point of view. “Extremist” has long been a dirty word in the national lexicon, particularly over the course of the two-decade-long summer that lasted, give or take a few interruptions, from the end of World War II to the mid-1960s. Those who dissented from the prevailing ideology of American exceptionalism—that is, America is special, better, greater than any other nation on the planet—or who called attention to the discrepancy between our leaders’ lofty rhetoric and the conduct of one administration after another were branded with the “e” word.

Extremists came in two flavors, right and left. Both were routinely vilified, the former as the lunatic fringe with their tinfoil hats and tales of alien abduction, the latter as un-Americans, laying the groundwork for Uncle Joe Stalin’s imminent takeover of the United States. But right or left, they were excluded from the mainstream—from its practices, its discourse or, as we now say, the national conversation.

Today, the battered centrists who are still walking and talking continue to use the term as a derogatory epithet, along with cognates like “divisive” and “controversial,” or, more colorfully, “wackos,” as Senator John McCain called Donald Trump’s supporters during the 2016 presidential primary.