The producers of "The Seduction" are evidently banking on a public without memory or discrimination. It hasn't been that long since "Tattoo" and "The Fan" triggered outbursts of derisive merriment by wallowing in the same premise--celebrity heroine stalked and terrorized by psychotic admirer. Opening today at area theaters, "The Seduction" merely underbids the competition, sinking into deeper ruts of hypocritical and nonsensical scumminess.

Morgan Fairchild, who has specialized in scheming hussies on television soap operas, day and night, is perversely miscast as a conventional exploitation thriller heroine, anxious and helpless in the face of sexual menace. The pornographic outlook behind this flimsy pretense of demure respectability is apparent from the outset, when Fairchild is introduced swimming in the nude one evening at her posh Bel Air residence. The pool seems to have been illuminated from underneath especially for the delectation of peeping Toms, like the agitated neighbor up the hill--Andrew Stevens as a young photographer nurturing an unhealthy infatuation with mermaid Fairchild, a TV anchorwoman. He can't be the only one sneaking looks, although he's obviously the nut case. One imagines the Goodyear blimp hovering over Fairchild's patio on clear nights.

At poolside, boyfriend Michael Sarrazin, a two-fisted reporter, confides, "I like looking at you," to which Fairchild moistly replies, "I like being looked at," encouraging peepers in the audience along with the peeper next door, by implication.

The cinematographer, Mac Ahlberg, once directed sultry, soft-core imports, notably "I, a Woman" and its sequel. He retains a glossy touch, but Fairchild proves such a vapid, blond-zombie object of erotic fixation on the big screen that old-timers may wonder nostalgically: Whatever happened to Ahlberg's erstwhile leading lady, the smoldering Essy Persson? The director, David Schmoeller, gropes for stylistic identity in a way calculated to make you feel even older: He's the first blatant, inept imitator of Brian De Palma.

Forcing his creepy intentions on the heroine, Stevens is allowed the run of places like her home and TV studio, where he mischievously slips a mash note into her script, causing hilarious hysterics when she mechanically reads it off the teleprompter. Although Sarrazin's best pal is a gruff cop played by Vince Edwards, the authorities show a convenient reluctance to interfere with Stevens' shenanigans, even when they become self-evidently illegal and dangerous.

The whole point of the absurdly contrived plot is that Stevens actually brings out the insatiable she-demon lurking behind Fairchild's blandly composed fac,ade. This switcheroo is perhaps the oldest porno dodge of them all--exceeding the expectations of the man who craves her, the woman reveals herself as more of a wanton than he can handle. The ultimate verification of the heroine's fundamental sluttiness is reserved for the denouement, an elaborately stupefying sequence that begins with Stevens interrupting Fairchild and Sarrazin as they copulate in a hot tub and concludes with the haunting suggestion that only a merciful death can save Stevens from being overwhelmed by the erotic ferocity unleashed in his dream girl, who snarls endearments like "Do it!" and "I oughta kill you, you're not a man!"

The unsavory nature of the concept is softened to a considerable extent by the ridiculous nature of the depiction. The performers are obliged to stumble through such a prolonged, outrageous dance of death that the stupidity of it all tends to obscure the viciousness of it all.

Stevens showed a flair for portraying smugly self-righteous menaces in De Palma's "The Fury" that becomes prematurely threadbare in the dopier context of "The Seduction." Nevertheless, his fleeting, sneaky grin is perhaps the only deliberate source of humor in the show. A transparent fraud and histrionic washout as a figure of sympathy, Fairchild will presumably return to more congenial make-believe as a troublemaking sexual predator on "Flamingo Road." She might have possibilities as a vampire's consort or a comic strip villainess. Her most striking features lend themselves to sinister camp: long, shockingly bony fingers and nostrils slanted so far upward that they seem almost perpendicular. The big screen can magnify things in devastating ways. "The Seduction" reveals that Morgan Fairchild has the oddest nose ever seen outside the pages of Dick Tracy.