Sandra Day O'Connor

“ The State's imposition of medical treatment on an unwilling competent adult necessarily involves some form of restraint and intrusion. A seriously ill or dying patient whose wishes are not honored may feel a captive of the machinery required for life-sustaining measures or other medical interventions. Such forced treatment may burden that individual's liberty interests as much as any state coercion. ”

“ Requiring a competent adult to endure such procedures against her will burdens the patient's liberty, dignity, and freedom to determine the course of her own treatment. Accordingly, the liberty guaranteed by the Due Process Clause must protect, if it protects anything, an individual's deeply personal decision to reject medical treatment, including the artificial delivery of food and water. ”

“ In my view, such a duty may well be constitutionally required to protect the patient's liberty interest in refusing medical treatment. Few individuals provide explicit oral or written instructions regarding their intent to refuse medical treatment should they become incompetent. [1] States which decline to consider any evidence other than such instructions may frequently fail to honor a patient's intent. Such failures might be avoided if the State considered an equally probative source of evidence: the patient's appointment of a proxy to make health care decisions on her behalf. ”