WHAT A PERFECT TITLE. True Confessions. It has a gamey, drug-store-magazine sleaziness, hinting of muscle-bound stories about husky heroes and fallen ladies. Yet the name demands a double-take. Maybe this movie--with a Catholic priest as its central character--does show us what confession really does, or should, mean.

And what a perfect place. Los Angeles in the late 1940s. Growing faster than anyone could imagine, much less control, the city encouraged reckless passions and unclean souls. Money and sex ruled over millions of greedy and lusty supplicants. And the millions had to contend only with each other because the rest of the world--either by design or by default--had decided to let Los Angeles grow on its own. Winner take all.

And what a perfect cast. Robert De Niro and Robert Duvall. Mr. Inside and Mr. Outside. De Niro is the id unleashed, the man whose characters wear emotional scars like merit badges, who can contain nothing. The slow-witted ball-player of Bang the Drum Slowly, Travis of Taxi Driver and Jake of Raging Bull all share a public-ness of neurosis that make De Niro's roles almost painful to watch. Duvall keeps it inside, waiting to explode. He is, in a way, almost scarier, because the energy is all potential, temporarily under wraps. The consiglieri of Godfather I and II, the capitalist visionary of Network, and, most of all, Col. Kilgore of Apocalypse Now can never exactly make clear--as De Niro always does--what has gone wrong inside and what that means.

True Confessions smelled like...victory.

And that is what makes its shortcomings all the more disappointing. Its potential, while not totally unrealized, remains largely unexploited; and because True Confessions looked so good from a distance, it suffers all the more up close. Not that it is a bad movie--not that at all--it is just not nearly as good as it could be.

The opening certainly has promise. Two brothers meet in the desert chapel where one of them is a priest. They talk uneasily of old times, careful to stay away from still-raw wounds. They are settling old debts peacefully, ready to die. The scene then cuts abruptly to an ornate cathedral, where the priest is presiding over a wedding about 20 years earlier. The impression is of great power in his hands; apparently by mere force of his personality, the priest has harnessed all that this magnificent scene can offer. He is in control.

This masterful manipulation of the way a scene looks is what True Confessions so obviously lacks for the rest of the picture. Ulu Grosbard's bland and uninteresting direction more often looks like a television situation comedy than a major feature film. Not only are the colors and backgrounds either washed-out or meaningless, but their lifelessness saps the movie of any feeling for the location or the era. Besides the old cars and wide-lapelled suits there is little hint of where or when the movie is taking place.

EVEN BIGGER PROBLEMS, however, are raised by the screen-play, a collaboration of the husband-and-wife team of John Gregory Dunne and Joan Didion. Working from Dunne's novel, the screenwriters apparently felt obliged not to graft any artificial eloquence onto characters who would not normally speak that way. Which is fine. The problems arise when Dunne and Didion substitute a peculiar, grunting short-hand that limits the characters and leaves the curious unenlightened. The poor dialogue, combined with the writers' need to explain a complicated and ever-changing plot, result in a dusultory and lifeless narrative.

And even the plot raises some troubling questions. It concerns the efforts of a young and ambitious priest named Desmond Spellacy (De Niro), and his brother, Tom an L.A. detective (Duvall), to resolve the gruesome murder of a young and fallen lady. Tom's investigations lead (inconclusively) to one of the biggest contributors to the Catholic Church in southern California, the archdiocese in which Desmond's considerable ambitions lie. To its credit, True Confessions does not seek a tidy ending that will send the folks home happy, but rather explores the complication and ambiguities of this sordid situation; the message in this movie of all losers and no winners is grim indeed. But because of the weakness of its explication, that message loses the resonance it might have had in a better film.

But to dwell excessively on True Confessions' failings is to treat it--and the viewer--unfairly. De Niro alone makes the experience worthwhile. The role is somewhat uncharacteristic; as a priest, he must keep his emotions and lusts hidden, but their supression makes them that much more interesting. The desire for power dominates Des, consumes him; he revels in bureaucratic wars as well as more public displays of his control. Yet the genius of De Niro's Des is that he knows how badly he wants power, and he senses how tenuous his position might be--in both practical and moral terms. Perhaps that is why Des spends so much time cleaning his hands; he knows what he is trying to remove, but his ambition will not let him do it. Very few actors can exploit this internal tension the way that De Niro does, as he leads Des toward his inevitable and tragic downfall.

Duvall faces a tougher time with his role, largely because of an incompletely drawn character, and consequently he cannot evoke him as clearly. The origin of Tom's passion--which is directed mostly at nailing Des's crooked benefactor--seems obscure, especially compared to Des's obvious motivation. Sibling rivalry is part of it, but not all. Tom may be seeking a kind of absolution for leading a life so much less holy than his brother's, but that too seems inadequate to explain his obsessive vendetta. Not even Duvall's gritty and angry performance can make it clear. Perhaps there is no explanation at all; perhaps the nervous, frustrated Tom--hands rubbing relentlessly on the table, feet and eyes never idling--simply has stored up too much resentment over the years and must disgorge it somewhere. We never know, and the film suffers.

True Confessions certainly will not bore anyone; nor will it insult the intelligence nor test the patience. A solid citizen of the movie world, it probably will age well and linger pleasantly in the mind. But with the raw material available to its creators, it could have done more, made more of a difference. Like its ultimately disappointed priest, True Confessions might have walked with the angels, but instead settled for life with us mortals.