"Saint Jack," which slipped quietly into the K-B Janus this week, is a peculiarly displaced movie about a peculiarly displaced person, an exiled American named Jack Flowers who aspires to find contentment as the proprietor of an elegant brothel in Singapore.

The story covers his checkered career from about 1971 to 1975, although it becomes a little hazy because of the monotonous objectivity of Peter Bogdanovich's direction.

It appears that Jack's activities and eventual setbacks are meant to suggest some allegorical parallel to the collapse of American intervention in Vietnam - and the general decline of Western imperial influence in the Orient.

It also appears as if the screenplay lost in the process of transposition from Paul Theroux's original novel.

Although Theroux shares screen-writing credit with Bogdanovich and Howard Sackler, crucial explanatory and reflective material is still wanting.

Future movie scholars may enjoy speculating on Bogdanovich's motives for choosing this story to revive his career after the resounding flops of "At Long Last Love" and Nickelodeon." It may reflect a healthy instinct for the sort of contemporary, profane, idiomatic literary material that led to his initial triumph with "The Last Picture Show," It may also reflect a dismaying, self-pitying sense of identification with the tarnished exile Jack, who may be a hustler and pimp, but salvages shreds of integrity and compassion.

Jack, played by Ben Gazarra, is first encountered running errands for a miserly Chinese merchant while pimping on the side. He strikes up a friendship with a British accountant played by Denholm Elliott who visits Singapore occasionally from his home in Hong Kong in order to audit the merchant's books.

Jack succeeds in establishing his brothel. But when local gangsters terrorize him and wreck the joint, he goes to work for an occasional customer, played by Bogdanovich, who has some connection with the U.S. Army and persuades him to run the vice concessions of a new "R & R" spa for American soldiers on leave from Vietnam.

When the Americans pull out of the war, Jack remains as an errand boy for the Bogdanovich character, now supervising dirty tricks for someone back in Washington. The death of his British friend and a particularly nasty assignment combine to disillusion Jack with his status, and the story ends on a "High Noon" note, with Jack chucking a bad job and walking off to confront an uncertain future.

Despite Gazarra's backlog of roles as a tough customer, the movie sentimentalizes Jack's Finer Instincts in a way that makes it difficult to believe he was ever prepared to survive in a basically squalid profession.

It's not unthinkable that a brothel owner would have his thoughtful, compassionate side, but it takes some doing to make the point believable in a modern urban setting. And the material could use sharper structural and domestic breaks. "Saint Jack" doesn't succeed, although it has effective setting in the exotic, elegaic vistas of Singapore emphasized by Robby Muller, the gifted German cinematographer who collaborated on several films with Wim Wenders, including "The American Friend."

But "Saint Jack" never makes a unified, conclusive emotional or thematic impression. It's as if Bogdanovich had managed to get back on the right track but was still unsure of which direction to go and how to build up a head of steam.