As US Armed Forces Radio DJ Adrian Cronauer, dumped in Saigon, in '65, Williams reveals how easy it is to hang a slim, bathetic idea on a virtuoso performance. Cronauer is your archetypal all-American anti-hero, an achingly funny, irreverent motormouth with a taste for hot soul and a subversive vision of the Vietnam conflict as a mad Wizard of Oz scenario which enrages the top brass as inevitably as it boosts the morale of the grunts. Williams' rendition of the broadcasting sequences is terrific, as speedily inventive as the comic's finest stand-up moments, even though Levinson has an irritating habit of cutting away to Cronauer's colleagues and audience cracking up, simply to show that the guy's funny. But the story itself is bunk. Besides the DJ's heroic set-to with petty-minded superiors, there's a crass romance with a shy young Vietnamese, and a friendship with her brother, which allows our fine liberal protagonist to play great white god to the gooks. Offering only hackneyed insights into the war, the film makes for stodgy drama. But Williams' manic monologues behind the mike are worth anybody's money.