Gore Vidal and William F. Buckley Jr. preparing for one of their televised debates, from the documentary “Best of Enemies.” (Magnolia Pictures)

In 1968, executives at ratings-hungry ABC hired two of the country’s more erudite public intellectuals to render judgment on that summer’s presidential conventions. What they might have expected was illuminating, elevated debate. What they got was a level of discourse that, by comparison, makes “Jane, you ignorant slut” sound like genteel repartee.

If irreconcilable differences are the hallmark of our current political era, its founding fathers may well have been Gore Vidal and William F. Buckley Jr. The subjects of Robert Gordon and Morgan Neville’s documentary “Best of Enemies,” (opening Friday, Aug. 7 at E Street Cinema), they came to ABC’s jerry-built soundstage at the Republican convention in Miami with little in common but contempt for each other.

To Buckley, “Vidal was the devil,” says biographer Fred Kaplan, while Vidal thought that Buckley’s conservative politics were, at best, undemocratic. “They really do despise each other,” observes Christopher Hitchens, whom Gordon and Neville interviewed in 2010, a month or so before the diagnosis of the cancer that killed him the following year. (“We thought the film would be ideal for the 2012 election,” Gordon says. “We didn’t hold off for 2016. It just took that long.”)

As the film shows, what ensued in Miami, and then in Chicago, was a rhetorical knife fight. There’s barely a pretense of objectivity, each man looking for a chink in the other’s armor, fashioning each comment into an insult and then Buckley — having been deemed a “crypto-Nazi” by his opponent — melting down in the heat of the Democratic convention in Chicago and calling Vidal a “queer.” (Something for which, the film posits, Buckley never forgave himself.)

It all made for “great television,” little of which had been appearing at that time on ABC. It had no Cronkite, no Huntley-Brinkley, no credibility as a news source. It was ranked third among the networks. “They would have been fourth,” notes former NBC News president Richard Wald, “but there were only three.” As Nation columnist Eric Alterman (also in the movie) wrote in his 1992 study “Sound & Fury: The Making of the Punditocracy,” ABC was searching for something that would distinguish its coverage. And the idea of pairing Buckley and the unpredictable Vidal had come from Buckley himself — “albeit in a back-handed manner.”

The heated 1968 debates between Buckley and Vidal at the presidential conventions set the tone for many of the confrontational shows on television today. (ABC Photo Archives/ABC via Getty Images/Magnolia Pictures)

“The network had asked him to name a liberal with whom he could profitably spar during the convention coverage,” Alterman wrote, “and Buckley replied that he would appear with any non-Communist, but he would prefer it not be that ‘philosophical degenerate,’ Gore Vidal.

“ ‘Bingo,’ said the men at ABC.”

As a programming strategy, the whole affair would lead to such confrontational-by-design “debate” shows as “Agronsky & Co.” (and its more opinionated descendant, “Inside Washington,” both produced by Post-Newsweek); the “Point/Counterpoint” showdowns on “60 Minutes” between Shana Alexander and James J. Kirkpatrick (which inspired the “Saturday Night Live” parody cited above); “The McLaughlin Group”; CNN’s cacophonous “Crossfire” (famously brought down by Jon Stewart); and whatever explosions are currently heard nightly on Fox and MSNBC.

“It may be that it marked both the beginning and end of television debate,” says Lawrence O’Donnell, host of “The Last Word” on MSNBC. “Buckley showed up with a kind of Yale notion of debate, a certain set of rules — ‘This is the way we do it, we share the stage, ideas will be offered, I will critique yours, you will critique mine.’ ” Vidal was perfectly capable of engaging on a purely policy level, “but he chose very deliberately to try to hurt the other person. And out of Buckley’s rage came pain and this horrible outburst toward Vidal.

“Ultimately, that is the element of the debate that has lived longest in our TV discussion culture,” O’Donnell says. “We see it all the time, whether it’s the host going after the guest, or guest after host, and it is ugly TV. And what Buckley understood immediately was that the worst thing that you can do in this forum is have it turn ugly. There are people who call that good TV. I personally hate it. And I’ve slipped into it. Which is why I’m sympathetic to how tempers flare. It’s an inch away all the time.”

Gordon and Neville have individually made numerous music documentaries (Neville won an Oscar for 2013’s “20 Feet from Stardom”), but as Gordon puts it, music is a lens through which they examine other things, including race and class.

“I think of myself as a cultural filmmaker,” Neville says. “I’ve made lots of movies on art and literature and music, and this is a movie less about politics than about media and the culture of politics. We said from the beginning, we didn’t want to make a film about the arguments, because that’s a political film. We wanted to make a movie about how we argue, and that’s the cultural film.”

How exactly Vidal and Buckley argue — via lofty diction, engorged vocabularies and patrician inflection — would seem to make them impossible for today’s TV, despite the lasting legacy of their debating tactics.

“They represent the last gasp of the old oratorical culture,” says John McWhorter, who teaches linguistics at Columbia University and appears in the film. “Between 1960 and ’70, the shift in the way Americans used language was massive, part of a huge shift toward informality in general. There was no longer a sense that language used in public was to be dressed up, the way a man put on a hat. It was different from casual language. Now, the whole idea of ‘making a speech’ has become archaic. Today, we call it ‘giving a talk.’ ”

Buckley, an author, conservative thinker and founder and editor of National Review, was familiar with the infant medium of television — he’d begun a 33-year career hosting “Firing Line” in 1966. Vidal, the autodidactic polymath, intimate of the Kennedy White House and a best-selling author of historical fiction (“Lincoln,” “Burr,” “Washington, D.C.”) simply got under Buckley’s skin — his authorship of the transsexual farce “Myra Breckinridge” went a long way toward accomplishing that. But Buckley’s effete mannerisms were also in Vidal’s cross hairs.

“They’re both gay-baiting each other,” Neville notes.

“From the first debate,” Gordon adds.

“What’s funny,” Neville says, “is Vidal telling Buckley ‘Myra Breckinridge is based entirely on you.’ Gore is trying to play with Buckley’s image and trying to get him to lose his temper, which he does.” What the two say to each other is frequently rife with innuendo — some of it, seemingly, absolutely filthy.

Buckley fans may find their hero getting the upper hand in the arena of straight debate. “He’s a known interrupter,” Gordon says, laughing. “You watch ‘Firing Line’ and one of his chief debating tactics is to interrupt and divert. If you’re about to answer something he didn’t think you were going to answer — just watch the Noam Chomsky ‘Firing Line.’ Chomsky, for 10 minutes, takes every question and tries to answer and finally says, ‘Please! Let me answer a question!’ ”

Ultimately, Vidal and Buckley seem slightly antique, save for their lasting influence on how political discussion is conducted on TV. Noisily. Sometimes incoherently. Occasionally, as Buckley experienced, with bad feelings that don’t go away. (The two men apparently loathed each other until the day they died, Buckley in 2008, Vidal in 2012.)

“I completely understand Buckley’s mourning over it,” O’Donnell says. “He’s embarrassed and shamed over it, and what television doesn’t have is the outlet to which we can express that. Someone yells at someone, it gets ugly and television doesn’t have the moment where you can say, ‘You know, I think that was kind of crazy, I think that went a little crazy, I’m sorry. . . .’ ”

It would be revolutionary. It might even make good television.

Anderson is a freelance writer.