The Cruzan ruling is intrinsically limited because it is only permissive. It upholds Missouri’s law that prohibits guardians from authorizing the termination of life support for their wards but does not prevent Missouri or other states from allowing guardians such authority. (Missouri subsequently passed a comprehensive “living will” law.) It upholds Missouri’s right to require a patient’s intentions to be proved by clear and convincing evidence but does not prevent states from using less rigorous criteria to determine a patient’s wishes.

Justice Rehnquist, in a rare example of preventive law advice from the bench, stressed the importance of using living wills and durable powers of attorney. Since these were not at issue in the case, this advice is not law, but it is a useful prediction of the court’s future direction.

Medical care providers in states such as Missouri should note that the majority opinion, and Justice Sandra Day O’Connor’s concurring opinion, imply that the state may be bound to follow the requests of a patient-appointed surrogate. This would give a surrogate appointed by a patient’s durable power of attorney more authority than a guardian appointed under restrictive state guardianship laws. [Mishkin DB. You don’t need a judge to terminate treatment. J Intensive Care Med. 1990;5:5201–5204.]

It is critical to appreciate that the public debate over termination of life support is driven in part by a desire not to waste medical care on patients who will not benefit from it. The problem is determining just who these patients are. Nancy Cruzan clearly does not benefit (in the sense of improved prognosis) from her medical care. Yet there are thousands of close calls for everyone in a similar condition. Given the enormous pressure by medical insurers and the federal government on physicians’ and patients’ families to terminate medical care, relaxed rules for substituted consent may not be the best solution to the problems of those in Cruzan’s condition.