The case of Terri Schiavo, a young woman who spent 15 years in a persistent vegetative state, has emerged as a watershed in debates over end-of-life care. While many observers had thought the right to refuse medical treatment was well established, this case split a family, divided a nation, and counfounded physicians, legislators, and many of the people they treated or represented. In renewing debates over the importance of advance directives, the...