The life and death of Terri Schiavo - intensely public, highly polarizing and played out around the clock on the Internet and television- has become a touchstone in American culture. Rarely have the forces of politics, religion and medicine collided so spectacularly, and with such potential for lasting effect. Ms. Schiavo, the profoundly incapacitated woman whose family split over whether she would have preferred to live or die, forced Americans into a national conversation about the end of life. Her case raised questions about the role of government in private family decisions. But her legacy may be that she brought...