Illustration: David Klein

In one version, Joe Biden’s banana-republic thugs invade the home of a blameless former president and ransack his wife’s dress closet. In an alternate version, representatives of Merrick Garland’s long-suffering Justice Department call at Mar-a-Lago to see if they might retrieve top-secret nuclear codes that Donald Trump pilfered from the White House, no doubt with intent to blackmail the world, like Dr. Evil.

We are used to the media’s Rashomon Effect, named after Akira Kurosawa’s 1950 film that offered alternate and mutually contradictory accounts of a samurai’s murder. So which witness is the audience supposed to believe this time? MSNBC? Fox News? Someone isn’t telling the truth.

Americans have long since grown, as it were, nostalgic for reality. They grope for the truth in a labyrinth of outlandish story lines. A master theme of the left (stated approximately): The Orange Man is the Red Queen of White Supremacy. A favorite on the right: In regions of the left’s many weirdnesses, men are women, and women men—whatever their hearts desire. Men have babies, and women probably don’t exist at all. The metaphysics of America’s political and cultural story lines have gone meta, which means that they have adapted new technologies (the trillion screens) to the oldest sleight-of-hand practiced by confidence men, totalitarians, intellectuals and the producers of cable television news.

Since the time of Herodotus, history has been shaped less by facts than by half-truths, rumors, outright lies, ideologies, daydreams and ardent misconceptions. These narrative energies weave themselves into story lines—self-myths and morality plays. Anyone trying to understand the American crisis should think about the trouble that story telling gets people into.

Consider the narratives that precipitated the American Civil War. The South had its story, a conviction of its own righteousness that was strong enough to keep the Confederate states fighting a war that left their plantations in ashes and their economy in ruins. Jefferson Davis kept repeating that the people of the South must be free to choose their own way of life. He and other slaveholders said they were “defending freedom.” And they believed it.

So the most consequential narrative line may be howlingly at odds with the truth. Abraham Lincoln’s story line turned Davis’s upside-down. Their stories were so mutually contradictory that the entire country went into convulsions and, by and by, Gen. P.G.T. Beauregard found himself obliged to shell Fort Sumter.

But the heroic story line of one period may do mischief in the next. The narrative of the civil-rights movement of the early 1960s became powerful in shaping the country’s moral, political and cultural drama, not only in the ’60s but in its evolution over the next half-century.

The early civil-rights movement (a hero’s story that coalesced, at last, in the martyrdom of Martin Luther King Jr. ) occurred at a moment when television news—a powerful new story-telling medium—began to reorganize the American conscience on a national basis and turned journalism into a medium of moral generalization.

Nearly every house had a set of rabbit ears. Television news rose to the occasion of the new historical material: The Kennedys and their telegenic Camelot, the (briefly) terrifying Cuban missile crisis, the assassination in Dallas—and all the while, down South, a continuing drama of police dogs, fire hoses, church bombings and white racists screaming at valiant, frightened black children trying to integrate the public schools. Local whites beat the Freedom Riders bloody or murdered young idealists of either color.

That civil-rights morality play, unambiguous and righteous in its story lines, succeeded almost too well in its effects. It offered a titanic clash of archetypes. A consensus of the storytellers ordained that the Good Guys were of one type—the pure of heart, the selfless elites, saints and martyrs, all of them virtuously leftist in their politics and soon, in the Vietnam time, to make up the armies of dissent against that misbegotten war. The Bad Guys represented another type: They were rednecks, bigots and white supremacists. They became, in the fullness of time and in the eyes of the left, the followers of Mr. Trump. The storytellers’ crude but powerful version said that the villains of that earlier time morphed, over generations, into the deplorables of MAGAland.

The stereotype represented unjust, inaccurate story telling, and it wronged about half the country. Beware. There’s an even deeper business at work: It is a truth of human nature and of story telling that you may, in the telling and retelling of a tale, conjure in reality the very demon that, a moment ago, you only imagined. The left, for example, might unconsciously contrive to make itself as awful and ridiculous as Tucker Carlson wants it to be. And the same thing might occur in the other direction. It’s strange how this happens—a fatal kind of wish-fulfillment. When a country gets overmastered by its narrative exaggerations, it may be doomed.

Update the archetypes. Ditch the sanctimony. A country may be destroyed by indulging its archaic premises and the smug, self-righteous stories it tells itself.

Mr. Morrow is a senior fellow at the Ethics and Public Policy Center. His latest book is “The Noise of Typewriters: Remembering Journalism,” forthcoming in January.