There’s a scene during the final 20 minutes of A Face in the Crowd — the strikingly prescient and enduringly potent 1957 drama that airs at 7 p.m. Wednesday on TCM (Turner Classic Movies) as part of a tribute to the late, great Andy Griffith — that has sufficient smash-mouth impact to make you forget, if only for a few minutes, that you ever saw the same actor play the ingratiating peacekeeper of Mayberry.

Three years before he assumed the lead role in the long-running sitcom that bore his name and ensured his immortality, Griffith mesmerized moviegoers with his galvanizing performance as Larry “Lonesome” Rhodes, an ingratiatingly folksy fraud who’s discovered by a broadcast journalist (Patricia Neal) in a small-town Arkansas jail, hired as a tale-spinning, guitar-strumming entertainer at her radio station and launched as a local superstar on a relentless trajectory toward national celebrity.

Right from the start, Marcia Jeffries, the aforementioned journalist, has ample reason to believe that this good-ol’-boy is a ne’er-do-well whose artless sincerity is more apparent than real. Still, she goes along for the ride — motivated, evidently, by equal measures of infatuation and ambition — when Lonesome Rhodes is hired away by a TV station in Memphis.

That is where they meet Mel Miller (Walter Matthau), a bookish and bespectacled TV writer who’s repeatedly ribbed by the casually anti-intellectual Rhodes for his Vanderbilt education. (I don’t have to tell you that this guy crushes on Marcia, do I?) More important, Memphis also is where they meet Joey DePalma (Anthony Franciosa), the conniving office assistant to the mattress store owner who buys commercial spots on Rhodes’ TV show, and is so infuriated by Rhodes’ mocking presentation of his ads that he’s only partly mollified when his sales start to skyrocket.

Joey is the one who sells Rhodes, a budding regional phenomenon, to Manhattan advertising agencies.

One thing leads to another, Rhodes — in one of the movie’s funniest sequences — suggests a surefire way to sell a vitamin supplement of dubious worth, and pretty soon the “Arkansas Traveler” (as Rhodes is nicknamed) is reaching a devoted national audience of 50 million viewers and rising.

But wait, there’s more: The retired general (Percy Waram) whose company produces the vitamin supplement — which, weirdly enough, is none-too-subtly pitched as a 1950s version of Viagra — sees Rhodes as a potential “wielder of opinion” who could utilize his aw-sucks soft-sell shtick to promote widespread fealty to “a responsible elite.” Which would make Rhodes a valuable asset in the general’s campaign to push a stuffy isolationist senator (Marshall Neilan) as a viable Presidential candidate.

The longer he basks in public adulation as host of a top-rated variety show, however, the more Rhodes is convinced of his superiority to his viewers, most of whom he secretly despises as credulous fools, and his intimates. He claims to love Marcia — but he marries, more or less on a whim, Betty Lou Fleckum (Lee Remick), a 17-year-old baton-twirling cutie, mainly because he’s intimidated by Marcia’s independence, and feels safer with what he assumes (wrongly, or course) is a docile bimbette.

And when Rhodes decides to start a different type of national TV show, Lonesome Rhodes’ Cracker Barrel, in which he’ll offer conservative political commentary camouflaged as nuggets of country-boy wisdom, he has little trouble bending to his will both the general, who grudgingly signs on as a sponsor, and the senator, who dutifully drops by to make disparaging comments about such radical leftie constructs as social security and unemployment insurance.

“I’m not just an entertainer,” Rhodes rants while browbeating the general. “I’m an influence . . . A force.”

That brings us to the scene where, after sending Betty Lou into exile for her infidelity, Rhodes pays a late night visit to Marcia’s Manhattan apartment and, while confiding in her, drops any pretense that he’s anything like the good-hearted homespun sage he pretends to be on TV.

Sure, he admits, he’s backing the senator for president — selling him like any other product, really — because the candidate has promised him a newly created cabinet post, Secretary for National Morale. And because Rhodes knows damn well that he can get this guy into the White House.

“This whole country’s just like my flock of sheep,” Rhodes rants while Marcia blanches. “Rednecks. Crackers. Hillbillies. Hausfraus. Shut-ins. Peapickers. Everybody who’s got to jump when someone else blows the whistle . . .

“They’re mine,” Rhodes insists, absolutely certain of his mastery of the unwashed masses. “I own ‘em. They think like I do.

“Only they’re more stupid than I am. So I got to think for them.”

Marcia listens attentively. And fearfully. And then, without fully realizing at first what goal she has improvised, she sets out to destroy the man Mel Miller has aptly described as a “demagogue in denim.”

Psychic Filmmaking?

Like many movies that are years (if not decades) ahead of their time, A Face in the Crowd was neither warmly embraced by audiences nor universally praised by critics during its initial theatrical release. During subsequent decades, however, the film — directed by Elia Kazan and written by Budd Schulberg three years after they memorably collaborated for On the Waterfront — has attained the status of an essential and influential classic, and now is widely admired as one of the relatively few movies (along with Network, Quiz Show and a small handful of others) to fully comprehend and vividly convey the immense power of mass media to shape opinions, create icons — and, at its worst, deceive millions.

The name Lonesome Rhodes has evolved into a kinda-sorta shorthand for any sort of telegenic huckster whose affects a beguiling Everyman manner to sell products and/or propaganda. When Keith Olbermann used to sneeringly refer to Glenn “Lonesome Rhodes” Beck, his taunt struck many — including, I’ll admit, yours truly — as devastatingly accurate.

And when Rick Perry collapsed as a Presidential candidate during his notorious “Oops!” moment at a nationally broadcast debate, it was hard for some movie fans not to recall Rhodes’ climactic self-destruction during an unguarded moment of on-the-air, open-mic candor

Of course, anyone who wants to characterize A Face of the Crowd as a cautionary tale about media manipulation by treacherous right-wingers must also acknowledge that Kazan (who died in 2003) and Schulberg (who made it all the way to 2009) infuriated folks on the Left back in the 1950s — and, indeed, continue to be viewed unkindly by many liberals in Hollywood and elsewhere — because the filmmakers, both of them disillusioned ex-members of the Communist Party, infamously named names while testifying before the House Un-American Activities Committee.

And while they lost many friends because of their actions, they remained steadfast in their assertions that they were motivated by love of country, not fear of blacklisting.

And yet: In his 1988 autobiography, Kazan noted with some bemusement that, years after his and Schulberg’s HUAC testimonies, A Face in the Crowd received a rave review in the Communist Party’s West Coast People’s World newspaper — and a withering pan in the right-wing journal Counterattack. And while critics and academics have suggested everyone from Arthur Godfrey to Will Rogers as real-life inspirations for Lonesome Rhodes, the late director deemed it more important that Schulberg “anticipated” another charismatic entertainer with political ambitions: Ronald Reagan.

As for Andy Griffith: It’s practically impossible to overestimate the irresistible appeal of Sheriff Andy Taylor, his beloved sitcom alter ego, a character that seemed to embody all the best qualities of a loving father, a reliable friend, a folksy sage, and a droll yet compassionate observer of human foibles.

At the same time, however, it’s doubtful that even Griffith would have claimed that throughout his half-century as a stage, screen and television actor, he ever had a role as complexly multifaceted, or gave a performance as fearlessly full-bodied, as he did when he made his big-screen debut in A Face in the Crowd.