In a classic episode of the CNN debate show “Crossfire,” the grand imperial wizard of the Ku Klux Klan was interrogated from the Left and the Right.

Liberal Tom Braden mixed eloquent denunciations of racism with mordant mockery (he frequently addressed the Klansman as “Mr. Wizard”). Conservative Pat Buchanan challenged their guest’s pretensions of representing a patriotic organization, pointing out that Klansmen march under flags symbolizing the Nazis so many American troops died fighting while hating the black soldiers killed in service of the United States.

Mr. Wizard protested that his hosts had him all wrong, that he was actually at the helm of a civil rights group, of sorts, for whites. “We believe at this point in time the white Americans are being treated as second-class citizens,” the Klan leader said. “That the federal laws, the civil right laws, have created a dual system of justice in this country, a set of federal laws that protects the interests of minorities and state and local laws that represent the interests of white people.”

When David Duke traded in his own white hood and robe for a more respectable business suit, he draped his efforts in this kind of lingo, calling one of his organizations the National Association for the Advancement of White People (the name had previously been used by a 1950s segregationist).

Braden’s masterful dissection of the Klan leader’s worldview was rooted in the truth. So was Buchanan’s more subtle indictment — though it was likely to be more persuasive to any viewers who might have been tempted by Mr. Wizard’s appeals.

This 1982 “Crossfire” episode came to mind after the generally hostile reaction to a New York Times profile of a racist who looked less like a grand imperial wizard than an otherwise ordinary guy. Some felt the lack of explicit condemnation contributed to “normalizing” neo-Nazis, while others alleged there was nothing particularly abnormal about racism in a country that elected Donald Trump president.

As if on cue, President Trump tweeted out factually dubious anti-Muslim videos on Wednesday.

Too many liberals have responded to Trump by concluding that many of their countrymen really are irredeemable deplorables — a designation the president used to his advantage during last year's campaign — and have abandoned the idea that argument or moral suasion can do much good on racially charged issues.

Your Trump-voting uncle is at best a racist troglodyte to be reluctantly endured during a Thanksgiving meal. He is at worst someone to be read out of American society.

This kind of sentiment, like that of the unhinged campus liberal fulminating against whites — “I hate you, because you shouldn’t exist” — may be marginal. And there are undoubtedly times when the Right irresponsibly inflates its importance.

Yet when a presidential candidate is booed and made to apologize for saying “all lives matter,” when major newspapers publish op-eds expressing skepticism about the possibility of meaningful interracial friendship with whites or editorialize that Taylor Swift must be a secret envoy of the alt-right, and when a senior member of Congress notes that the women making sexual harassment claims against a fellow lawmaker are all white, people tend to take notice.

Some of these examples may be less damning in context (Rep. James Clyburn, D-S.C., has denied the precise quotes attributed to him). But the argument for sanitizing white racism as a form of legitimate identity politics seems to be resonating with well-meaning people in a way that it once did not. It seems like a bad time to stop making counterarguments.

We are far from the point where the extremes are mainstream. David Duke may claim to be vindicated by Trump, but last year he received 3.4 percent of the vote in Louisiana, a state where he once could break 40 percent. But in the Trump era, neither the Left nor the Right is offering an Americanism in which all Americans feel included.