Michael Caine, who has been delivering superb performances for four decades, offers one of his finest ever in a political drama about America's early involvement in Vietnam. The film itself, while admirable for its ambition, falls short of the high-water mark set by its lead actor. Like Sunset Boulevard, The Quiet American starts with a corpse floating in water. It's Saigon in 1952 and the dead body is that of Alden Pyle (Fraser), a Yank. Pyle was, we learn in flashbacks, a seemingly nice guy bringing medical supplies to Vietnam. Or at least that's what he told Thomas Fowler (Caine), a hard-drinking English journalist, when they first met. Soon Fowler suspects that this quiet American may not be who he seems. When Pyle successfully makes a play for the married Fowler's Vietnamese mistress (Do), it's symbolic of America's increasing interest in Vietnam itself; Pyle is actually a CIA agent intent on destabilizing the political status quo. Based on Graham Greene's 1955 novel (previously filmed in 1958) and directed with an appreciation for nuance by Phillip Noyce (The Bone Collector), American isn't as tight as it could be. There are arid stretches, and Fraser's approach to his character seems muddled. Caine, though, by turns burned-out, engaged, enraged and finally overwhelmingly sad, is reason enough to see it. (Quiet opens this month in New York City and Los Angeles for two weeks to qualify for Oscars and then reopens nationwide in February.)