The last movie directed by Martin Ritt was "Casey's Shadow," the most undeserving box-office failure of 1978. Perhaps that misfortune preyed on Ritt's mind while he was directing the newly arrived "Norma Rae," a picture so desperate to be ingratiating that it all but pleads for a title like "Love Me With All Your Heart!"

Ritt has certainly changed his tone. Maybe for the better from a commercial standpoint, definitely for the worse from a dramatic one. The leisurely, observant, cumulatively affecting style of "Casey's Shadow" has been exchanged for an anxious, choppy, bombastic exposition in "Norma Rae," which purports to show how a harried young Southern textile worker finds her self-respect by helping organize a union local.

Although "Casey's Shadow" appeared to be victimized by defective advertising, Ritt may have feared that the admirably straightforward, lucid exposition was somehow at fault, perhaps not "punchy" enough. At any rate, he doesn't trust the audience to meet him halfway in "Norma Rae." He goes after them like a punchy fighter trying to score a tenth-round konckout, aiming topical, inspirational, romantic and rabble-rousing haymakers in the general direction of the old heartstrings.

Sally Field embodies the title character with considerable sincerity, and she's already being promoted for next year's Academy Award by admiring reviewers in Hollywood. She looks wonderful in the opening sequence, an evocative scene-setter which depicts Norma Rae at work in the textile mill. You're drawn to the stubbornly intent expression on her face as she tends her machine in the din of the factory. The combination of softness and grittiness, the impression of prematurely careworn youthfulness, is peculiarly appealing and promising.

Unfortunately, the movie comes so unraveled that in retrospect the images of loose strands of fiber in the air seem more significant than the character of the heroine or the bleak factory environment. The screenplay by Irving Ravetch and Harriet Frank Jr., who previously collaborated with Ritt on "The Long Hot Summer," "The Sound and the Fury," "Hud," "Hombre" and "Conrack," turns out to be a pile of loose thematic and emotional strands. At the fade-in and fadeout their intentions seem clear, even transparently sympathetic, but the connecting material is balled-up and gummed-up.

"Norma Rae" takes place in an illdefined socio-economic present in a small Southern mill town, doubled by Opelika, Ala. I don't know if unions make a practice of organizing workers in such places by importing ethnic outsiders guaranteed to stick out like a sore thumb. Ravetch and Frank pretend that they do and aggravate the problem by characterizing their sore thumb, a New York Jewish organizer named Reuben, as a sanctimonious benefactor, ennobling Norma Rae in the glow of his platitudinous wisdom, do-gooding virtue and platonic affection.

Reuben is an absurd cross of Conrack with Molly Goldberg, rendered even more grotesque by the efforts of Ron Leibman to suppress his explosive comic vitality and come on revoltingly wise, warm and wonderful. Despite a likable performance by Jon Voight, "Conrack" was a misfire; Ritt and the Ravetches failed to do justice to Pat Conroy's richly detailed, self-critical account of his teaching experiences in "The Water Is Wide." Invoking the same character in "Norma Rae" and disguising him as a lovably ingenious, big-hearted Jew, the filmmakers succeed in adding mawkish insult to well-meaning injury.

It's doubtful if any actor could redeem Reuben's most fatuous and condescending remarks, obviously cherished by the screenwriters. Perhaps it's to Leibman's credit that he keeps a straight face when Norma Rae is required to ask what makes the Jews different and Reuben replies simply, "History." Never theless, one would feel better if Leibman had his tongue in his cheek.

Beau Bridges, cast in a marginal role as a fellow worker who courts and marries Norma Rae, creates a far more attractive impression than Leibman. Although Bridges establishes an easier rapport with Field and his character obviously has more in common with Norma Rae, he's shunted aside and ultimately compelled to sit dumbly by when Reuben informs him that Norma Rae has been liberated by union activism: "She's a free woman. Maybe you can live with that, maybe you can't."

Curiously for this day and age, the relationship between Reuben and Norma Rae is supposed to remain strictly platonic. The characters are given a protracted skinny-dipping scene without a sexual follow-up to the dip. Although many a satisfying platonic love flourishes and endues in real life, the filmmakers have not depicted one that makes a particle of sense or inspires a whisper of pathos.

It will be a maddening joke if Leibman turns out to be a crowd-pleaser in this misbegotten role. Many of us still wish he had been cast as Lenny Bruce, a role that might have made all the difference to his career and "lenny" too. Leibman's smart, manic, toothy presence always put one pleasurably in mind of a Jewish Bugs Bunny. in "Norma Rae" you can watch his Bugs Bunny deteriorate into Elmer Fud.

The puzzling nature of the romantic triangle in "Norma Rae" is duplicated in the social conflicts. The plot might have had a chance if Field and Bridges enacted a love story set against a union organizing battle. Given their feckless behavior, it seems unlikely that Reuben and Norma Rae could recruit a catfish between them.

Moreover, the continuity is so ramshackle that scenes never accumulate and build in a dramatically expressive way. There's no follow -- through when Norma Rae's father, played by Pat Hingle, suffers a death directly attributable to working conditions in factory. The climactic union vote seems to come out of left field.

As a rule, the filmmakers manufacture fake climaxes every 10 or 15 minutes, poop out and lapse into forgetfulness, just as if they were structuring the material for television. "Norma Rae" seems to reflect the confusion of veteran filmmakers so eager to please that they cease to think straight.