It's party time, 2:30 in the morning, and George Clooney, a dapper, urbane Hollywood star of the old school, is surrounded, not surprisingly, by a small sea of women oohing and aahing over his latest movie. Each wants to stake a lasting claim on his bachelor body, as she digs her hand deeply into the small of his tuxedoed back. Each is rewarded with his devilish smile, and a gaze that signals rapt attention. Seemingly tireless, Clooney has been going full tilt since the previous morning, plugging his latest work, and he has hours to go before he sleeps. Famous for his revelry, his posse of loyal buddies, his practical jokes, the party boy will stay out until 8 a.m., when he finally dispatches his driver and calls it a night.

Off screen, Clooney exudes the same easy charm that defines his movie persona--not something that holds true of most movie stars. But the actor, it turns out, has surprises up his sleeve. The above party was no Hollywood glamorama but part of the opening-night celebrations of the New York Film Festival. The most selective showcase of world cinema, the festival has opened with films by Almodovar, Altman and Kieslowski. This year it was "Good Night, and Good Luck," a film co-written and directed by the former star of "ER." Made for a mere $7 million, it's a 90-minute black-and-white movie about journalist Edward R. Murrow and his historic confrontation with Red-baiting Wisconsin Sen. Joe McCarthy in the 1950s. David Strathairn plays the grave, fearless Murrow, McCarthy is represented only in old newsreel footage and Clooney disappears into an un-showy role as CBS producer Fred Friendly. It's a passionate, serious, impeccably crafted movie tackling a subject Clooney cares about deeply: the duty of journalism to speak truth to power. It also happens to be the most compelling American movie of the year so far.

Who could have seen this coming? Less than 10 years ago, when the romantic comedy "One Fine Day" appeared, it was an open question whether Clooney would make the leap from TV to movie stardom. "Three Kings" and "Out of Sight" were both initially unsuccessful but may wind up DVD classics. Along with "Ocean's Eleven," they established Clooney as a legitimate heir to Cary Grant. It turns out he had even bigger objectives in mind, one of which is to restore honor to the term "liberal." It infuriates him that it's become a dirty word. "It blows my mind," he says, "because [unlike conservatives] we don't have to put the word 'compassionate' in front of it to say we actually give a s--t about people. I'm going to keep saying 'liberal' as loud as I can and as often as I can."

"Good Night, and Good Luck"--Clooney's second outing as a director, after the unsuccessful but intriguing "Confessions of a Dangerous Mind"--homes in on a historic moment that occurred before he was born. Yet it's personal filmmaking at its most heartfelt, revealing as much about Clooney, finally, as it does about the cold war. Murrow, who first became famous for his radio broadcasts from London during World War II and then as the host of CBS's "See It Now," was the role model for Clooney's father, Nick, an anchorman in Cincinnati and Lexington, Ky. The movie is Clooney's tribute to both Murrow and his own role model: his dad.

Clooney has no interest in the conventional contours of the biopic: you'll learn nothing here of Murrow's private life. Modest in scale, the movie is set almost entirely within the CBS studios (you never see the sky, except in an old Alcoa commercial). When Murrow decides to take on McCarthy, whose reckless investigations into alleged communist infiltration of the government spread postwar paranoia across the land, fear seeps into the newsroom. Murrow knows, as does CBS boss William Paley (Frank Langella), that McCarthy will retaliate by questioning his loyalty and smearing his name. He's putting the entire network at risk.

Knowing the outcome doesn't diminish the tension a bit, and Clooney and Grant Heslov's fine-chiseled script resonates with contemporary relevance. "We cannot defend freedom abroad by deserting it at home," Murrow said in his 1954 McCarthy broadcast. The senator used fear to undermine traditional American freedoms and equate dissent with disloyalty. Any resemblance to the current administration's exploitation of 9/11 is no accident.

In his life, and in his movies, Clooney is fascinated by male camaraderie. His elaborate choreography of the teamwork that goes into television journalism is unsurpassed. The period detail is impeccable, from the ubiquitous cigarette smoking to the courtly male chauvinism (all the women are "dears" as they are sent out to fetch coffee and copies of The New York Times). You can feel the influence of Robert Altman in the playful overlapping dialogue and the sinuous, roving camera that darts from studio to studio. (Robert Elswit's cinematography and Stephen Mirrione's editing are stunning.) On one studio set is jazz singer Dianne Reeves, who serves as a kind of musical Greek chorus, her soulful songs playing counterpoint to the drama. The movie's secret weapon is its glamour.

But its passion, which catches you at unexpected moments, is concentrated in Strathairn's mesmerizing performance. Utterly still, yet roiling with inner intensity, he gets Murrow's sorrowful gravitas, as well as a hint of his vanity. The movie is framed by a speech Murrow gave in 1958 decrying television's embrace of triviality and escapism, and exhorting it to resist the corporate pressure to dumb down the public discourse. Clooney obviously shares these sentiments, but his civics lesson never feels hectoring or self-important. The style is the man: "Good Night" is a cri de coeur in the form of a smoky, understated seduction.

"Good Night" arrives, post-Katrina, at what feels like a watershed moment in the relationship between the press and the presidency, and a turnaround in the public's attitude toward TV news. Clooney wants us to remember what reporting at its best can be. "In the end it all comes down to journalists," he says, looking relaxed on the day of his movie's festival debut. "They're the first writers of history. There is no civil-rights movement without journalists. There is no end of McCarthy. It's been a tough time for journalists--if you ask a tough question of this administration, on a rare occasion when they have a press conference, you're put in the back of the room, or you're Maureen Dowd and you get your credentials pulled. To question anything about them is meant to be unpatriotic."

Clooney is an unreconstructed "actorvist" who'll defend any actor's right to make a political stink: "I love anybody who sticks their neck out." (He declines to campaign for candidates himself--he suspects his presence would do more harm than good--and prefers a less polarizing style than Michael Moore's.) Is a fun-loving liberal a contradiction in terms? Clooney is testing the theorem. This past year he found himself picking out restaurants for a casino that he and partner Randy Gerber will open in Las Vegas. "At the same time, I'm at the G8 summit in a room with Paul Wolfowitz and Bono trying to get $50 billion in relief for Africa," he says. "I'm in this weird place: I have this beautiful house in Italy and I have these social agendas. I don't want to give up that lifestyle because I enjoy it, but I also feel that I have a responsibility. So the way I try to rationalize that, and it may just be Irish-Catholic guilt, is, for instance, with this casino 25 percent of anything it makes will go to the Make Poverty History campaign. It's the only way I can reconcile being successful."

His casino will be a throwback to the Rat Pack era: there will be a dress code, big bands, a dance floor. "I have a romantic view of Vegas. I have a romantic view of a lot of things," he says. "I remember going and watching my Aunt Rosemary sing in Vegas, and you got dressed up to go to the casino. I miss that kind of class." He'd also like to revive the kind of filmmaking that made the '70s such an urgent, exciting era in Hollywood. Last Christmas he gave his friends a hundred DVDs as presents. "I spent a long time picking my favorite films between 1964 and '76." Movies like "Carnal Knowledge," "All the President's Men," "Network," "The Candidate," "Harold and Maude."

Later this year he'll appear in just that kind of movie, "Syriana," playing real-life CIA agent Robert Baer in a politically charged drama about oil, terrorism and the Middle East. Politically, he expects it will get him in "a lot of trouble." Artistically, it's his attempt as an actor to erase all his familiar traits. He hopes to be almost unrecognizable: he gained 30 pounds for the role, grew a beard and trimmed back his hairline. "This has to be a guy no one notices, because he's the spy who gets left out in the cold," he says. "I'm not as talented as I wish to be at acting. But I have an incredible appetite for trying new things."

His greatest acting job may be making it all look easy. If it's acting. Back at the after-party on opening night, he maintains his genial, pitch-perfect balance of confidence and self-deprecation. "Actorvist" and bon vivant; driven auteur and laid-back guy's guy; politician and prankster: if there are contradictions here, the seams don't show. His old supporter, CBS's Les Moonves, once said, "What you see on screen is what you get off screen." True. But it turns out to be only half the story.