““Now you are finding out there aren’t a lot of people waiting in line to take in someone who would put a baby in a microwave oven,’’ Lydia’s caseworker scolds.

““You know she never did anything remotely like that!’’ Courter retorts.

She’s still fighting the system. After five years as a part-time guardian, Courter, a 50-year-old novelist, filmmaker and mother of two, has emerged as one of the most articulate voices in the growing debate over how to make the nation’s child-welfare system more responsive to children. At a time when no one can agree who should rear the children of drug-addicted mothers, much less who has a rightful claim to Baby Richard or Baby M., Courter argues for putting kids’ needs first, ““erring on the side of the child.''

There are about 37,000 court-appointed guardians nationwide – compared with the estimated 500,000 children in substitute care. Their role is to help find the best home for a child, free of the conflicting biases of parents and caseworkers. When Courter volunteered in 1989, after reading about a 2-year-old foster child who was murdered by his stepfather, she saw guardianship as a bit of community service. Soon she was giving over vast chunks of her life to her young charges. These are the children of abuse and neglect, the offspring of drug-addicted mothers and HIV-positive fathers, kids whose families are too shattered to care for them. When they land in the system, everyone breathes a sigh of relief – then forgets them. Courter the idealist wants to save every child. Courter the pragmatist is content to be their voice. ““To the system,children are “trouble units’ in need of beds. One of the things I do is fight for them as people.''

Or she tries to. Courter vividly depicts the lunacy of a system that conspires against the very children it’s supposed to protect. Public agencies may be good at finding a bed and three squares, but what about emotional security? Courter’s villains are caseworkers like Mona, who perpetuated the microwave lie, even though a cursory probe would have found that Lydia was taking the rap for a bad-news boyfriend who had threatened to chop up her 10-year-old sister (not a baby) and put her in a microwave. Courter is just as critical of foster parents like Renata MacDougal, a dour, militaristic woman who would wipe her cat’s eyes with a tissue but took back the Walkman and cowboy boots she bought one of Courter’s charges for Christmas.

Beyond the bureaucrats lies society’s failure to define what it means by the ““best’’ interests of a child. The rules are play-as-you-go. When Courter took on Alicia, Cory and Richard Stevenson (like everyone else in the book, their identities have been changed), no one doubted that any home would be better than the one they came from. Their father, Red, had sexually abused Alicia and Richard. Their mother had long since split. Cory, 13, so desperately wanted to live with Red that he sabotaged eight placements in eight months. ““I knew that going back to his father would be disastrous. But I also knew that if he didn’t go back, he wouldn’t have closure,’’ said Courter, who built in ongoing oversight so the reunion would be safe.

What Courter wants now is nothing less than an overhaul of the child-welfare system. She champions the growing minority of researchers and advocates challenging the assumption that all children belong with their biological parents. Offering kids a permanent home should be the goal, they argue, and courts need to quickly sever the rights of parents who can’t or won’t measure up. Courter believes it doesn’t have to be all or nothing. Many parents, she says, could maintain secondary rights, guaranteeing a connection to their children. ““We throw tens of thousands of dollars’ worth of services to reunite a coke-addicted mother and her kids. But we have to make hard choices.’’ She’s not just spouting political or intellectual abstractions. Though Courter has lost track of the dollars and hoursshe’s spent as a guardian, she and herhusband, Philip, a documentary filmmaker, now plan to donate half their resources to childrens’ rights. Pity the poor children? Courter would rather stand up for them.