Around the time "Coming Home" was released, Jane Fonda gave an interview in which she took a gratuitous swipe at a former costar, Robert Redford. She claimed he had lost the dedication to social change and betterment he once professed.Redford evidently shrugged it off.

Later that year, he and Fonda were reunited in a romantic comedy called "The Electric Horseman," their first costarring vehicle since "Barefoot in the Park," a big hit in 1967. Ironically, "Horseman" seems to demonstrate that Fonda should never have questioned Redford's sincerity.

During the second, progressively lugubrious half of the far-from-electrifying film, now at area theaters, the pair conducts on on-the-road love affair that has Fonda virtually worshiping the rugged ground Redford's Last Natural Cowboy walks on. Ever diffident and gracious, Redford accepts the adoration without forcing Fonda's Overcivilized Woman of Fashion to grovel or get sickeningly apologetic about it.

After a crisp, amusing start, which established Redford's identity as a retired rodeo champion who has sunk into dissipation and self-loathing after signing on as the corporate promotional symbol for "Ranch Breakfast," a new ceral, "Horseman" gradually meanders up thematic and romantic dead ends.

Ranch Breakfast is manufactured by a division of AmpCo, a wicked conglomerate lusting for another acquisition, which holds a splashy convention at Caesar's Palace in Las Vegas. Redford, whose value to the company has been declining as he grows more drunk and less reliable, is nevertheless scheduled to ride another corporate symbol, a champion Thoroughbred named Rising Star, in the floor show.

One of the crucial unrationalized imbecilities of the screenplay credited to Robert Garland is the cruel fate AmpCo inflicts on Rising Star: The company has exploited this great stallion in a way that utterly defies financial, public relations or mere common sense. Instead of siring new champions, Rising Star is being shot full of steroids and tranquilizers and paraded around at conventions and supermarket openings.

In real life, it wouldn't take much prublicity to provoke outrage among dedicated horsemen or the general public. In the tendentious context of "The Electric Horseman," Redford -- a two-legged thoroughbred emasculated by his selling out to the corporation -- can only reassert his masculinity and rescue the animal by kidnaping him.

Moreover, he gets it into his addled head that Rising Star can fulfill his destiny only if he is turned loose, with a wild herd, as with Elsa the lioness in "Born Free." To assure this consummation, Redford leads pursuing lawmen on merry chases, incidentally subjecting the horse to a high risk of crippling injury.

But so what? Pure motives suffice in Hollywood liberal parables at their most elementary. The conflicts in "Horseman" are primitive black and white. In the same respect that the power company in "The China Syndrome" could be depicted taking regulations lightly or summoning a SWAT team to execute a rebellious employe, any villainous expediency goes for the conglomerate in "The Electric Horseman." Frustrated by the elusive Redford, AmpCo's chief (played by John Saxon) commands his flunkies to "Use the FBI! Use the state police!" Saxon ought to be twirling invisible moustaches.

Fonda turns up as a glittering TV journalist who has descended upon Las Vegas with her cassette reocrder and a Hispanic cameraman to cover the convention. She ends up making contact with Redford after he absconds with the horse. Initially interested in the story as a mere scoop, she becomes so impressed with Redford's dedication that she joins him on the outlaw road to Wild Horse Valley, or wherever.

On the trail she falls so hard for his manly virtue that she's composing diary entries that make the very pages blush, begging, "Hit me, yell at me, slap me!" to make amends for her even thinking of exploiting him. Inviting as it is, Redford declines this tender request.

Indeed, their love affair is a collector's item of stellar difference and condescension. They treat one another more as guests on the Dinah Shore show than a man and woman falling in love. There's a remarkable amount of ego stroking, with the jouranlist telling the cowboy how good he is and the cowboy replying in kind, though without the breathless hints of erotic submission.

Somehow, Redford gets the best of the mutual-admiration colloquy. He's so much the confident man in the saddle that he doesn't even stoop to make a play for the smitten Fonda. His consideration is expressed by never making her feel badly about being such a suspectible, indeed swoony, female.

This dizzy affair seems to betray what might have been a more tangy, funnier movie. Redford is certainly more amusing in the introductory scenes, where he evokes the Nick Nolte character in North Dallas Forty" and is attended by that great natural performer, Willie Nelson, who is underutilized in a now-you-see-it, now-you-don't-role as the hero's patient manager.

(Fortunately, you hear him singing on the soundtrack now and then.)

The more virtuous Redford's cowboy is alleged to become, the more of a simple-minded fraud he actually becomes. The low point may be his speech explaining the kidnaping of the horse, an oration that wows Fonda, perhaps because the self-righteous tone rings a bell:

"Maybe they bought him, but there's some rights you can't buy. This horse deserved a better life, and I'm gonna see that he gets it . . . I'm gonna turn him loose. Maybe it won't work, but at least he'll have a shot."

No need to buy a Christmas present for Redford and Fonda this year. They've already made a movie calculated to smother each other in garlands of self-congratulation.