The child protective system (CPS), shaped by federal law forty years ago and run on the state and county levels in the United States, offered in utopian fashion the hope of preventing all possible child abuse or neglect. In response, legislators enacted a spate of vague laws that poorly defined such categories as "abuse" and "neglect," and granted the CPS sweeping powers to intrude into families, often on the basis of nothing more than anonymous complaints about standard childrearing practices. This arrangement, which followed from the questionable assertion of the existence of a crisis of...