When you once believed something that now strikes you as absurd, even unhinged, it can be almost impossible to summon that feeling of credulity again. Maybe that is why it is easier for most of us to forget, rather than to try and explain, the Satanic-abuse scare that gripped this country in the early 80's -- the myth that Devil-worshipers had set up shop in our day-care centers, where their clever adepts were raping and sodomizing children, practicing ritual sacrifice, shedding their clothes, drinking blood and eating feces, all unnoticed by parents, neighbors and the authorities.

Of course, if you were one of the dozens of people prosecuted in these cases, one of those who spent years in jails and prisons on wildly implausible charges, one of those separated from your own children, forgetting would not be an option. You would spend the rest of your life wondering what hit you, what cleaved your life into the before and the after, the daylight and the nightmare. And this would be your constant preoccupation even if you were eventually exonerated -- perhaps especially then. For if most people no longer believed in your diabolical guilt, why had they once believed in it, and so fervently?

Peggy McMartin Buckey, who died on Dec. 15, at 74, was surely still wondering. She was the paradigmatic victim of ritual-child-abuse hysteria: a middle-aged woman who worked in a day-care center run by her family and who had, until the day she was indicted, led an uneventful and unobtrusive life.

Buckey's ordeal began in 1983, when the mother of a 2 1/2-year-old who attended the McMartin preschool in Manhattan Beach, Calif., called the police to report that her son had been sodomized there. It didn't matter that the woman was eventually found to be a paranoid schizophrenic, and that the accusations she made -- of teachers who took children on airplane rides to Palm Springs and lured them into a labyrinth of underground tunnels where the accused "flew in the air" and others were "all dressed up as witches" -- defied logic. Satanic-abuse experts, therapists and social workers soon descended on the school and, with a barrage of suggestive, not to say coercive, questioning techniques (lavishly praising children who "disclosed," telling those who denied the abuse that they were "dumb," introducing salacious possibilities that children had never mentioned), produced increasingly elaborate and grotesque testimonials from young children at the school.

"Believe the children" was the sanctified slogan of the moment -- but what it came to mean, all too often, was believe them unless they say they were not abused. It didn't matter that no trace of the secret tunnels was ever found, that no physical evidence corroborated the charges (a black robe seized by the police as a Satanic get-up turned out to be Peggy's graduation gown), that none of the kiddie porn the abusers were supposedly manufacturing ever turned up, despite an extensive investigation by the F.B.I. and Interpol, that no parents who stopped by during the day had ever noticed, say, the killing of a horse. It didn't matter that most child abuse -- which after all does exist in real and horrifying form -- takes place not in day-care centers but in the home, indeed within the family. The prosecution charged forward nonetheless, with a seven-year trial that became the longest and, at a cost of $15 million, the most expensive criminal trial in American history. It resulted in not a single conviction, though seven people were charged in the McMartin case, on a total of 135 counts -- just a series of deadlocks, acquittals and mistrials. Buckey served two years in jail, and her son, Raymond, served five. They spent their life's savings on lawyers' fees and in the end went "through hell" and "lost everything," as she put it after her 1990 acquittal.

Yet even now, the legacy of McMartin and other cases like it (Wee Care in Maplewood, N.J.; Little Rascals in Edenton, N.C.; Fells Acres in Malden, Mass.) is with us. It's with us -- this is the sad part -- in policies that discourage day-care workers and teachers from hugging children or from changing diapers without a witness, lest they be accused of something untoward. It is also with us -- this is the good part -- in improved methods of questioning young witnesses.

Over the last few years, it has become commonplace to describe the ritual-abuse trials as witch hunts, and surely that's as good a metaphor as any. Yet in one important way, it isn't quite right. In the prototypical witch hunts in Europe and in the Massachusetts colony, the accused were often scapegoats for some calamity -- disease, bad harvests, the birth of a deformed child. In the witch hunts of the 80's, there was no such injury to be avenged or repaired. There was, however, a psychological need to be fulfilled. Our willingness to believe in ritual abuse was grounded in anxiety about putting children in day care at a time when mothers were entering the work force in unprecedented numbers. It was as though there were some dark, self-defeating relief in trading niggling everyday doubts about our children's care for our absolute worst fears -- for a story with monsters, not just human beings who didn't always treat our kids exactly as we would like; for a fate so horrific and bizarre that no parent, no matter how vigilant, could have ever prevented it.

By now, the screaming meemies about day care have settled into a chronic low-level ambivalence -- children get more colds when they're in day care, but then again, they don't get asthma as much; they may be slightly less attached to their mothers, but they may also be more sociable; and so on -- a constant, uneasy seesawing of emotion that we mostly keep at bay. But ambivalence is a difficult state of mind to sustain; the temptation to replace it with a more Manichaean vision is always close at hand.