"The Great Santini" falls considerably short of the greatness a number of admiring reviewers have attributed to it, but it's a good thing they cared enough to go overboard.

Without that support, the picture would have been denied a fair shot at a theatrical public, and for all its awkwardness and mawkishness, "Santini" deserves the shot. It has an authentic core of family drama and humor that could stir a large public.

It is based on Pat Conroy's original novel, a semi-autobiographical account of life with father when father happens to be a uniquely intimidating and overpowering presence -- in this case a gung-ho Marine fighter pilot, Col. Wilbur "Bull" Meechum, who assumes command of a squadron at the Marine base near Beaufort, S.C., in 1962 as the movie version begins. The book was an uproarious, revealing portrait of an American military family for perhaps two-thirds of its length. The maddeningly domineering yet also irresistibly funny Bull, played with dubious bravado by Robert Duvall in the film, was established with stunning comic impact, and the family scenes drew one into a setting that appeared authentically close and volatile, a hotbed of intimacy, conflict and hilarity.

The central conflict in the story concerns the understandable resentment of young Ben Meechum, a high school senior, to his father's tyrannical, authoritarian personality, imposed with particular rigor and sometimes downright cruelty on his eldest son, whom Bull imagines he's toughening up even when he's acting arbitrary or brutal.

The book began to waver at the point were Conroy became reluctant to attempt a deeper exploration of the characters of Bull and his gracious, loyal wife Lillian (flawlessly embodied in the film by Bylthe Danner -- who once again seems poised for a great movie performance but doesn't get enough material to go over the top emotionally). Conroy couldn't seem to imagine his way inside the psyches of these people when the story required a fuller understanding of what brought them together and kept them together, despite the strain that Bull's career and overbearing personality created for his gentle Lillian and the four children she endeavored to shield from his occasional outrages.

Controy seemed to be inhibited because Bull and Lillian originated a bit too close to home: The book was dedicated to his parents, "Frances 'Peggy' Conroy, the grandest of mothers and teachers" and "Colonel Donald Conroy, U.S.M.C. Ret., the grandest of fathers and Marine aviators." Presumably Ben -- portrayed by Michael O'Keefe in the movie -- was the author's alter-ego.

The difficulty was the Conroy couldn't account for the father's side of the conflict in the later chapters, so the central conflict was never resolved. The book seemed to go off on a tangent, indulging a melodramatic digression about racial violence, in which the son of the Meechum's black maid is assulted by a gang of rednecks, and eventually losing sight of Bull Altogether.

The movie compounds the novel's eventual dramatic weakness. There's a vast difference in quality between Pat Conroy's accomplished prose style and screenwriter-director Lewis John Carlino's uncertain filmmaking style, yet Carlino follows the plot of the book faithfully, reproducing the diffuse, anticimactic elements while reducing the general quality of perception and creating fresh difficulties.

Carlino seems to be at his shakiest with the situation that counts most -- the father-son conflict -- and I think he leaves both Duvall and O'Keefe to Flounder when their performances are despersately in need of discipline and support. Nevertheless, the essential nature of the conflict is so familiar and the implications so compelling that the material sometimes transcends the director's inadequacies. Certain episodes are effectively depicted, notably a one-on-one half-court game between Bull and Ben that exposes the ugliest side of the father's personality. Even when you wince at the poor staging of some sequences -- for example, a showdown high-school basketball game that fails miserably to sustain the needed illusion of tumultuous, explosive tension -- the idea behind them may still churn up your emotions. The authentic aspects of the story are often too strong to destroy. e

The critical praise for Duvall's performance seems especially mystifying if one comes to the movie from the book. Duvall fails to impose himself physically in the way that one expects of the original Bull, who was big as well as ostentatiously tough. There should be no hesitation or doubt in Bull's self-assertion, but Duvall keeps breaking up the Cadences of his dialogue and flashing odd little expressions that seem totally out of character. It's as if he felt obliged to hint that he didn't share this guy's attitudes himself; just between us, the actor knows that Bull is often full of it too. Is it "vulnerability" that Duvall is trying to signal? If so, he's wasting it on the wrong Marine.

It's encouraging that the movie's theatrical revival, spearheaded by a rave from Rex Reed, occurred in the wake of its telecast over HBO under an alternate title, "The Ace." The "Santini" case suggests that cable television exposure isn't necessarily a deterrent to theatrical exhibition. In some cases it may rescue or enhance the prospects of a feature condemned to premature oblivion by a discouraged or defeatist movie company.