In a movie defined by empty spaces where flesh-and-blood characters should be-Robert Duvall's lifeguard-turned-gonzo-warrior Lt. Colonel Kilgore is the one substantial presence that keeps Apocalypse Now from floating away on its own ambivalent impulses. Duvall is on-screen for only 25 minutes in the first hour of the film, but much of what follows would not cohere without surf-nut Kilgore first leading his men into an odyssey of destruction as they search for the perfect wave. It's during this epically savage battle sequence that Duvall burns Kilgore into our memories, having Wagner pour forth from speakers on the attack helicopters as his boys rain death from above, and afterward spouting classic madman dialogue: "I love the smell of napalm in the morning--it smells like... victory!" But the subtleties that give Kilgore life as a character come through in smaller moments: Duvall's excited grin when he sees how the surf is breaking; the rational authority of his terse command cutting through the chaos: "I want my wounded out of there and in the hospital in 15 minutes. I want my men out."

When avowed right-wing writer John Milius scripted the original Apocalypse in 1969, his "Colonel Kharnage" was a gung-ho cartoon of the American soldier as killer, ready to murder a fellow soldier who steals his surfboard. Coppola's rewrite softened Kharnage into the more realistic Kilgore, but it took hard work and intelligence on Duvall's part to avoid the black-or-white traps that lefty Coppola and righty Milius set up for the character. Duvall adds a cruclal layer of humanity to Kilgore that makes him intriguing to hawks and doves alike, and articulates one of the tragedies of Vietnam: In a war with no agenda, the men who fought had to create their own. While Kilgore may indeed be crazy, Duvall makes him a madman you'd follow in spite of yourself. Asked about the wisdom of attacking an enemy stronghold simply because surfing conditions are primo, Kilgore shoots back: "Charlie don't surf!" This credo lacks all but the most twisted kind of logic, but Duvall's delivery makes it the final word on the subject.

Duvall's decision to play Kilgore as the ultimate father-figure--Colonel Dad-- is what saves his character from caricature, and he works the comically twisted edge into the man with ease. "Don't you worry," he tells a cowering soldier with a reassuring smile after ordering in a napalm strike, "we'll have this place cleaned up and ready in a jiffy, son!"

Duvall's Kilgore believes that frying human beings with jellied gasoline is just being efficient; the gleam in his cold blue eyes isn't madness, but satisfaction at a job well done. Duvall's last moments on screen are probably the movie's finest: Crouched on his haunches, Kilgore takes Willard into his confidence with a smile and a nod, and imparts his final wisdom: "Some day this war's gonna end..." The line, delivered not with irony, but wistfulness and satisfaction, sets Willard and the rest of us up for the journey toward Kurtz. The pattern of delusion that Duvall's sanguine tone makes infectious will prove to be the seed of "the horror, the horror."