It was probably appropriate that half the guests at a Manhattan screening of the new documentary “Inside Deep Throat” Monday night thought they’d come to watch a movie about Watergate. The other half, of course, knew they were there to look back on the days when porn legend Linda Lovelace and her co-star Harry Reems were making oral history together.

What both those 1970s melodramas, the political and the sexual, had in common was the brooding presence of President Nixon. Without his green-lighting of the Justice Department’s prosecution of Mr. Reems and the rest of the perpetrators of the 1972 “Deep Throat,” the old skin flick would have long ago passed into oblivion. As it was, it became the most profitable movie ever made. Its $25,000 production cost yielded over a $600 million payday – roughly a million bucks for each $40 invested. The money was collected nightly, in cash, by Mafia bagmen, their suitcases bulging with huge quantities of disappearing cash. “Deep Throat” had winner’s luck for everyone but its creators.

“Inside Deep Throat” appears headed for success, too, albeit on a smaller scale and with HBO substituting for the mob. The current FCC fatwa against any kind of network naughtiness adds the touch of lefty moralism needed to give the new documentary a chic marketing angle. Plus there’s a good red-state redemption story: Mr. Reems, whose “Deep Throat” fame petered out into a booze and drug addled stupor panhandling on Sunset Strip, is now a born-again Christian selling real estate in Park City, Utah. He was in attendance at Monday’s screening. His acting skills were always, erm, wooden and his hair is nearly white, but he looked craggy and spry.

I have to admit that I’m pretty tired at this point of listening to some of the clapped-out sexual crusaders featured in the documentary-guys like Hugh Hefner, who has spent the last 30 years sitting around in a dressing gown, holding forth on the importance of the liberties he bestowed on us all. Even so, it is worth seeing the documentary for its buoyant use of old footage, its hilarious interviews with some of the behind-the-camera schlemiels who actually made the original movie, and its Plato’s Retreat-like sense of the 1970s. It was touching to see how the director of “Deep Throat,” a former swinger and hair-salon owner named Gerard Damiano, and his cast and crew had no idea they were on the cultural cutting edge until Nixon, Jack Nicholson, and Warren Beatty told them they were.

As for the panel following the documentary, coming just one day after the first anniversary of Nipplegate at the Super Bowl it afforded a snapshot of where we are stuck in the Bush 2 culture wars.

With the film critic Elvis Mitchell moderating, the onstage chairs were occupied by feminist virago and porn scourge Catharine MacKinnon; media bloodhound and defense attorney Alan Dershowitz; hellcat publisher and former Bernard Kerik squeeze Judith Regan, who published Jenna Jameson’s bestselling memoir, and New Yorker journalist Peter Boyer, who was there because he made a PBS “Frontline” report about the porn business. (In his sly Southern drawl, Mr. Boyer reminded us that his film featured one Adam Glasser, a nice, polite Jewish boy with a doting mom, who made his fortune as a purveyor of anal porn under the name Seymore Butts and is now the Trump-like hero of his very own Showtime reality show, “Family Business.”)

Ms. MacKinnon, whose tight white face and 19th-century hairdo made her look like Carrie Nation on the South Beach diet, launched into a tirade about how “Inside Deep Throat” had failed to point out that Lovelace had been a victim of “throat rape.” (Lovelace couldn’t tell us herself because she is dead. One of the weaknesses of the documentary is the pathos of her story is largely ignored). Ms. MacKinnon’s “feminist fundamentalism” immediately came under fire from Mr. Dershowitz, who went on a stem-winder about how there is zero evidence of ill effects on society at large from pornography and how female sexual exploitation is no different from the exploitation of young black basketball players at school.

Ms. Regan’s melodic baritone then seemed to back up Ms. MacKinnon, albeit in a mode that still allowed her to have it all ways. Every porn star she has encountered, she said, is a victim of sexual abuse. Ms. Jameson is a deeply sad woman. Her “issues” are still “unresolved.” That’s why Ms. Regan helped her tell her story and titled the book “How to Make Love Like a Porn Star: A Cautionary Tale.”(Ms. Regan didn’t buy Ms. MacKinnon’s charge, however, that Lovelace had to be hypnotized in order to perform her sexual feats. “I took voice training,” Ms. Regan explained to me afterwards. “I’m pretty sure it can be done.”)

It all reminded me about the real source of nostalgia for that era: The comparatively dizzying level at which the cultural argument was conducted in those days. All that casual brilliance – not Ann Coulter versus Michael Moore but Norman Mailer versus Gore Vidal. It must have been fun to turn on the TV back then. Mr. Mailer’s big, teddy-bear head probably got that size by going on a talk show as good as Dick Cavett’s and knowing he was being listened to.

“What I remember from those times is a sense of exuberance and hope,” Erica Jong, who is also featured in the movie, told me. “We didn’t think it was a joke. We thought sexual freedom would bring world peace. We really thought that if people gave up their inhibitions the world would change. We were wrong.”

In the age of media excess there is no room for that kind of innocent earnestness. Cable culture drains all conviction with the need to pound any idea into an available niche. After the panel was over, half the women secretly found themselves agreeing more with Ms. MacKinnon than with either Mr. Dershowitz or the movie. They wouldn’t be caught dead saying so out loud, of course, for fear of being cast as a retro feminist or, worse, the kind of eye-popping theocon who wages war on SpongeBob SquarePants. That would be almost as uncool as admitting how much more sophisticated and entertaining the Super Bowl ads were under the FCC’s regrettable new strictures to keep it clean.