"Poor Joshua!" lamented Justice Harry Blackmun in his famous dissent. "Victim of repeated attacks by an irresponsible, bullying, obviously cowardly, and intemperate father, and abandoned by respondents who placed him in a dangerous predicament and who knew or learned what was going on, and yet did essentially nothing. . . ." Even so, the Supreme Court, by a 6-to-3 margin, absolved Wisconsin officials of any negligence in a case that had left a young...