There are fans of sincere musicians and daring visual artists who profess that their idols are all about their art. But I dare anyone to watch Sacha Baron Cohen dash naked through a full hotel ballroom full of shocked conventioneers in Borat, and tell me that there is an artist anywhere more fully committed to what he does--or who yields such breathtakingly brilliant results from that commitment.

As anyone knows who has followed Cohen from the BBC to HBO's Da Ali G Show, he has spent years honing satirical characters that seduce both celebrities and everyday people into moments of enlightening, savagely funny honesty. The Daily Show's deadpan interviewers may have taken this approach into the pop culture mainstream, but with the film debut of regular Ali G character Borat Sagdiyev, Cohen has taken guerrilla reality comedy to staggering new heights. Thanks to his willingness to push every possible boundary, Cohen and director Larry Charles have created not just the funniest movie of the year, but probably the best of any kind.

Cohen's Borat--a television personality from Kazakhstan whose personal hygiene is nearly as offensive as his ideas about women, Jews and the mentally handicapped--has appeared previously in improvised "interviews" over the years. But in this film's context, Borat has a more serious purpose. The lengthy sub-title Cultural Learnings of America for Make Benefit Glorious Nation of Kazakhstan describes an assignment by his government to visit the United States with his producer Azarat (Ken Davitian) and bring back information to help modernize the country. But after seeing an episode of Baywatch in his hotel room, Borat becomes obsessed with Pamela Anderson, and undertakes a cross-country quest from New York to California to find her.

That quest is more or less an excuse to get Borat out on the road, where he can mix and mingle with real heartland Americans. And the "real" part of that equation is what makes Borat so extraordinary. While Cohen gets plenty of comic mileage out of purely staged bits--like the "Running of the Jews" festival in his homeland, or a particularly disturbing hotel-room wrestling match between Borat and Azarat--he's at his finest when taking his fish-out-of-water routine straight to the people. The unsuspecting folk with whom Borat interacts never see it coming as he lures them into exposing their darkest sides. A gun shop owner responds to Borat's inquiry about the best weapon to hunt a Jew without hesitation: "9 mm." A rodeo attendee hears Borat describe his home country's (fictional) capital punishment policy for gays, and gleefully wishes it were the same in America. A trio of road-tripping frat boys shares less-than-enlightened views on male-female interactions. It's mind-boggling, jaw-dropping, and funny in a way that only the most painful truths can be.

But it only works because Cohen's dedication to the identity of Borat is so complete. It's impossible to watch Borat and not realize that Cohen puts himself at bodily risk to get some of his best material. He rolls through a tough section of Atlanta to learn street slang from African-American youths; he greets a subway rider with an attempt at a kiss, and has the guy threaten him for the effort; he's wrestled to the ground by security guards on more than one occasion. And not once in the middle of these scenes--when any sane person would consider it prudent to remove the mask and tell people to smile because they're on Candid Camera--does Cohen visibly break character. Some writers have compared Cohen's brand of full-contact humor with that of Andy Kaufman, but Kaufman often seemed more interested in sustaining a gag than in entertaining anyone else with it. Borat marks the creation of a performance as satisfying as it is ground-breaking; it's the comedic equivalent of watching Marlon Brando bring the Method to the masses for the first time.

Borat has already inspired hand-wringing by Jewish groups and others afraid that some viewers may not get the satirical joke behind the character's unabashed bigotry. Someone undoubtedly also thought that Swift's suggestion about turning Irish babies into lunch wasn't such a bad idea, either, but some realities can only be exposed by sneaking past the defenses of ignorance with strategic hyperbole. Sacha Baron Cohen has made a film that soars precisely because it hasn't been timidly focus-grouped and scrubbed clean of anything that could possibly give offense. Like Cohen himself, it's utterly fearless.

BORAT: CULTURAL LEARNINGS OF AMERICA FOR MAKE BENEFIT GLORIOUS NATION OF KAZAKHSTAN

**** (four stars out of four)

Starring: Sacha Baron Cohen, Ken Davitian.

Directed by Larry Charles

Rated R.