At a Slate party this week, a colleague and I got into a discussion of what kind of movie Borat (Twentieth Century Fox) is. Is it a parody? If so, what would it be parodying—the horny Kazakh journalists who clog American airwaves with their dirty malapropisms? (Honestly, if I have to see one moreof those guys on public-access cable …) Or is it a filmed reality show, like Jackass or Punk'd, in which nervy, obnoxious young men risk their dignity and at times their physical safety for the sheer joy of making fools of themselves and others?

I advanced the theory that perhaps Borat belongs to the tradition of the character-based spoof. Think of Peter Sellers in the original Pink Panther series or Mike Myers in the Austin Powers movies: comic performances so outsized they make the movie around them seem like mere decoration, an excuse for the character to exist. Sacha Baron Cohen's palpable physical glee in embodying the bumbling, humiliation-proof Borat at times recalls Myers' relationship to the furry, buck-toothed superspy, and Baron Cohen's virtuosity with accents and pratfalls can evoke Sellers.

But in spirit, Borat seems closest to last year's documentary The Aristocrats, which used an old chestnut of a vaudeville joke to investigate the darkest corners of our shared comic consciousness. Borat: Cultural Learnings of America for Make Benefit Glorious Nation of Kazakhstan is, in a literal sense, wildly funny. Its best jokes approach some savage, atavistic core of cultural taboo and make the viewer wonder: Is it really possible to laugh at this? But by the time you formulate that question, it's too late: You're already laughing.

For those residing in some hype-resistant biospheric dome, Baron Cohen plays Borat Sagdiyev, the Kazakh TV reporter who shows up in New York City with nothing but a few dollars, some "clothings," and "a jar of gypsy tears to protect from AIDS" and undertakes a low-budget television documentary about the exotic mores of the "U.S. & A." with his producer, Azamat (Ken Davitian), by his side. When Borat catches an episode of Baywatch on his hotel TV, he conceives a blind passion for Pamela Anderson and resolves to drive to L.A. to kidnap the actress in his bride-bag.

The basic Borat MO is familiar to anyone who's watched Da Ali G Show, the British (and later HBO) semireality show in which Baron Cohen, as one of three different personas, interviewed public figures with a deliberate cluelessness that forced his subjects to step outside their usual talking points. (For those who haven't had the cringeful pleasure, HBO will be running the entire series over the next week.) The faux-doc concept of the movie allows him to expand slightly on that formula, mixing real interviews with unsuspecting citizens and scripted conversations between Borat, Azamat, and other characters played by actors. Pamela Anderson, playing herself, is a real sport as the object of Borat's desire. (It's not clear whether Anderson was in on the actor's true identity or not, but it seems likely she was, having been the butt of his practical jokes before.)

In some encounters, Borat merely embarrasses his interlocutors, as when he returns from the bathroom at a formal dinner party with a plastic bag of his own feces, asking where to throw it away. These scenes are funny but one-note; after the initial burst of oh-no-he-didn't shock, you start to feel sorry for the victim. But in the film's most sobering scenes, Borat's enthusiastic projection of guileless ignorance somehow compels people to disclose their own deepest fears and prejudices. "Do you have slaves?" he asks a group of drunken frat boys who pick him up in their RV. "I wish!" crows one of the lads. A rancher at a rodeo (where, in real life, Baron Cohen was nearly assaulted for singing a pro-Kazakh version of "The Star-Spangled Banner") heartily approves when Borat mentions that gay men in his country are taken out and hung.

Does Borat go too far? It's hard to address that question in a movie as ruthlessly piety-demolishing as this one: Whatever particular group you choose to stand up for, you end up looking like a humorless fool. The Kazakh government has protested the representation of their country as uncivilized. Borat's taped response, which appears on the official Borat Web site, assures his audience that, "I have no connection with Mr. Cohen and fully support my government's decision to sue this Jew." Baron Cohen's refusal to give interviews out of character, and the strict separation he maintains between self and character in the public milieu, functions as a brilliant tactic for simultaneously besting and evading his critics. In essence, he's offending himself.

If there's any group that might have some legitimate grounds for offense in Borat, it's one that hasn't made much noise about the film yet: fat people. At 82 minutes, the movie zooms by, with virtually no dead spots—a real rarity in film comedies, even the funniest ones. But the film's longest set piece, and one of the few jokes that drags on too long for my taste, is a naked wrestling match between Borat and the morbidly obese Azamat. It's a gay joke and a fat joke at the same time. But while the gay joke is primarily a joke on the audience (got a problem with gay sex? Here, watch while one guy shoves his balls in another's face!), the fat joke is a joke on Ken Davitian's body. We laugh, not only because the sequence is so shamelessly raunchy, but because the actor's physique is so consummately unappealing. Maybe it's just because I'm an American woman with the requisite body issues, but that makes me feel kind of bad.

Borat is directed by Larry Charles, a director and producer of many episodes of Curb Your Enthusiasm, another classic in the I-can't-believe-he-just-said-that comedy canon. But Baron Cohen's jaw-dropping gall makes even Curb's Larry David look like a blushing wallflower. Whether you attribute that gall to fearless honesty or shameless crassitude is up to you. I'll just be over here, laughing so hard I aspirate my popcorn.