Chief Justice Rehnquist
delivered the opinion of the Court.
Petitioner Nancy Beth Cruzan was rendered incompetent as a result of severe injuries sustained during an automobile accident. Copetitioners Lester and Joyce Cruzan, Nancy’s parents and coguardians, sought a court order directing the withdrawal of their daughter’s artificial feeding and hydration equipment after it became apparent that she had virtually no chance of recovering her cognitive faculties. The Supreme Court of Missouri held that because there was no clear and convincing evidence of Nancy’s desire to have life-sustaining treatment withdrawn under such circumstances, her parents lacked authority to effectuate such a request. We granted certiorari, 492 U. S. 917 (1989), and now affirm.
On the night of January 11, 1983, Nancy Cruzan lost control of her car as she traveled down Elm Road in Jasper County, Missouri. The vehicle overturned, and Cruzan was discovered lying face down in a ditch without detectable respiratory or cardiac function. Paramedics were able to restore her breathing and heartbeat at the accident site, and she was transported to a hospital in an unconscious state. An attending neurosurgeon diagnosed her as having sustained probable cerebral contusions compounded by significant anoxia (lack of oxygen). The Missouri trial court in this case found that permanent brain damage generally results after 6 minutes in an anoxic state; it was estimated that Cru-zan was deprived of oxygen from 12 to 14 minutes. She remained in a coma for approximately three weeks and then progressed to an unconscious state in which she was able to orally ingest some nutrition. In order to ease feeding and' further the recovery, surgeons implanted a gastrostomy feeding and hydration tube in Cruzan with the consent of her then husband. Subsequent rehabilitative efforts proved unavailing. She now lies in a Missouri state hospital in what is commonly referred to as a persistent vegetative state: generally, a condition in which a person exhibits motor reflexes but evinces no indications of significant cognitive function. The State of Missouri is bearing the cost of her care.
After it had become apparent that Nancy Cruzan had virtually no chance of regaining her mental faculties, her parents asked hospital employees to terminate the artificial nutrition and hydration procedures. All agree that such a removal would cause her death. The employees refused to honor the request without court approval. The parents then sought and received authorization from the state trial court for termination. The court found that a person in Nancy’s condition had a fundamental right under the State and Federal Constitutions to refuse or direct the withdrawal of “death prolonging procedures.” App. to Pet. for Cert. A99. The court also found that Nancy’s “expressed thoughts at age twenty-five in somewhat serious conversation with a housemate friend that if sick or injured she would not wish to continue her life unless she could live at least halfway normally suggests that given her present condition she would not wish to continue on with her nutrition and hydration.” Id., at A97-A98.
The Supreme Court of Missouri reversed by a divided vote. The court recognized a right to refuse treatment embodied in the common-law doctrine of informed consent, but expressed skepticism about the application of that doctrine in the circumstances of this case. Cruzan v. Harmon, 760 S. W. 2d 408, 416-417 (1988) (en banc). The court also declined to read a broad right of privacy into the State Constitution which would “support the right of a person to refuse medical treatment in every circumstance,” and expressed doubt as to whether such a right existed under the United States Constitution. Id., at 417-418. It then decided that the Missouri Living Will statute, Mo. Rev. Stat. §459.010 et seq. (1986), embodied a state policy strongly favoring the preservation of life. 760 S. W. 2d, at 419-420. The court found that Cruzan’s statements to her roommate regarding her desire to live or die under certain conditions were “unreliable for the purpose of determining her intent,” id., at 424, “and thus insufficient to support the co-guardians[’] claim to exercise substituted judgment on Nancy’s behalf.” Id., at 426. It rejected the argument that Cruzan’s parents were entitled to order the termination of her medical treatment, concluding that “no person can assume that choice for an incompetent in the absence of the formalities required under Missouri’s Living Will statutes or the clear and convincing, inherently reliable evidence absent here.” Id., at 425. The court also expressed its view that “[b]road policy questions bearing on life and death are more properly addressed by representative assemblies” than judicial bodies. Id., at 426.
We granted certiorari to consider the question whether Cruzan has a right under the United States Constitution which would require the hospital to withdraw life-sustaining treatment from her under these circumstances.
At common law, even the touching of one person by another without consent and without legal justification was a battery. See W. Keeton, D. Dobbs, R. Keeton, & D. Owen, Prosser and Keeton on Law of Torts § 9, pp. 39-42 (5th ed. 1984). Before the turn of the century, this Court observed that “[n]o right is held more sacred, or is more carefully guarded, by the common law, than the right of every individual to the possession and control of his own person, free from all restraint or interference of others, unless by clear and unquestionable authority of law.” Union Pacific R. Co. v. Botsford, 141 U. S. 250, 251 (1891). This notion of bodily integrity has been embodied in the requirement that informed consent is generally required for medical treatment. Justice Cardozo, while on the Court of Appeals of New York, aptly described this doctrine: “Every human being of adult years and sound mind has a right to determine what shall be done with his own body; and a surgeon who performs an operation without his patient’s consent commits an assault, for which he is liable in damages.” Schloendorff v. Society of New York Hospital, 211 N. Y. 125, 129-130, 105 N. E. 92, 93 (1914). The informed consent doctrine has become firmly entrenched in American tort law. See Keeton, Dobbs, Keeton, & Owen, supra, §32, pp. 189-192; F. Rozovsky, Consent to Treatment, A Practical Guide 1-98 (2d ed. 1990).
The logical corollary of the doctrine of informed consent is that the patient generally possesses the right not to consent, that is, to refuse treatment. Until about 15 years ago and the seminal decision in In re Quinlan, 70 N. J. 10, 355 A. 2d 647, cert. denied sub nom. Garget v. New Jersey, 429 U. S. 922 (1976), the number of right-to-refuse-treatment decisions was relatively few. Most of the earlier cases involved patients who refused medical treatment forbidden by their religious beliefs, thus implicating First Amendment rights as well as common-law rights of self-determination. More recently, however, with the advance of medical technology capable of sustaining life well past the point where natural forces would have brought certain death in earlier times, cases involving the right to refuse life-sustaining treatment have burgeoned. See 760 S. W. 2d, at 412, n. 4 (collecting 54 reported decisions from 1976 through 1988).
In the Quinlan case, young Karen Quinlan suffered severe brain damage as the result of anoxia and entered a persistent vegetative state. Karen’s father sought judicial approval to disconnect his daughter’s respirator. The New Jersey Supreme Court granted the relief, holding that Karen had a right of privacy grounded in the Federal Constitution to terminate treatment. In re Quinlan, 70 N. J., at 38-42, 355 A. 2d, at 662-664. Recognizing that this right was not absolute, however, the court balanced it against asserted state interests. Noting that the State’s interest “weakens and the individual’s right to privacy grows as the degree of bodily invasion increases and the prognosis dims,” the court concluded that the state interests had to give way in that case. Id., at 41, 355 A. 2d, at 664. The court also concluded that the “only practical way” to prevent the loss of Karen’s privacy right due to her incompetence was to allow her guardian and family to decide “whether she would exercise it in these circumstances.” Ibid.
After Quinlan, however, most courts have based a right to refuse treatment either solely on the common-law right to informed consent or on both the common-law right and a constitutional privacy right. See L. Tribe, American Constitutional Law § 15-11, p. 1365 (2d ed. 1988). In Superintendent of Belchertown State School v. Saikewicz, 373 Mass. 728, 370 N. E. 2d 417 (1977), the Supreme Judicial Court of Massachusetts relied on both the right of privacy and the right of informed consent to permit the withholding of chemotherapy from a profoundly retarded 67-year-old man suffering from leukemia. Id., at 737-738, 370 N. E. 2d, at 424. Reasoning that an incompetent person retains the same rights as a competent individual “because the value of human dignity extends to both,” the court adopted a “substituted judgment” standard whereby courts were to determine what an incompetent individual’s decision would have been under the circumstances. Id., at 745, 752-753, 757-758, 370 N. E. 2d, at 427, 431, 434. Distilling certain state interests from prior case law — the preservation of life, the protection of the interests of innocent third parties, the prevention of suicide, and the maintenance of the ethical integrity of the medical profession — the court recognized the first interest as paramount and noted it was greatest when an affliction was curable, “as opposed to the State interest where, as here, the issue is not whether, but when, for how long, and at what cost to the individual [a] life may be briefly extended.” Id., at 742, 370 N. E. 2d, at 426.
In In re Storar, 52 N. Y. 2d 363, 420 N. E. 2d 64, cert. denied, 454 U. S. 858 (1981), the New York Court of Appeals declined to base a right to refuse treatment on a constitutional privacy right. Instead, it found such a right “adequately supported” by the informed consent doctrine. Id., at 376-377, 420 N. E. 2d, at 70. In In re Eichner (decided with In re Storar, supra), an 83-year-old man who had suffered brain damage from anoxia entered a vegetative state and was thus incompetent to consent to the removal of his respirator. The court, however, found it unnecessary to reach the question whether his rights could be exercised by others since it found the evidence clear and convincing from statements made by the patient when competent that he “did not want to be maintained in a vegetative coma by use of a respirator.” Id., at 380, 420 N. E. 2d, at 72. In the companion Storar case, a 52-year-old man suffering from bladder cancer had been profoundly retarded during most of his life. Implicitly rejecting the approach taken in Saikewicz, supra, the court reasoned that due to such life-long incompetency, “it is unrealistic to attempt to determine whether he would want to continue potentially life prolonging treatment if he were competent.” 52 N. Y. 2d, at 380, 420 N. E. 2d, at 72. As the evidence showed that the patient’s required blood transfusions did not involve excessive pain and without them his mental and physical abilities would deteriorate, the court concluded that it should not “allow an incompetent patient to bleed to death because someone, even someone as close as a parent or sibling, feels that this is best for one with an incurable disease.” Id., at 382, 420 N. E. 2d, at 73.
Many of the later cases build on the principles established in Quinlan, Saikewicz, and Storar/Eichner. For instance, in In re Conroy, 98 N. J. 321, 486 A. 2d 1209 (1985), the same court that decided Quinlan considered whether a nasogastric feeding tube could be removed from an 84-year-old incompetent nursing-home resident suffering irreversible mental and physical ailments. While recognizing that a federal right of privacy might apply in the case, the court, contrary to its approach in Quinlan, decided to base its decision on the common-law right to self-determination and informed consent. 98 N. J., at 348, 486 A. 2d, at 1223. “On balance, the right to self-determination ordinarily outweighs any countervailing state interests, and competent persons generally are permitted to refuse medical treatment, even at the risk of death. Most of the cases that have held otherwise, unless they involved the interest in protecting innocent third parties, have concerned the patient’s competency to make a rational and considered choice.” Id., at 353-354, 486 A. 2d, at 1225.
Reasoning that the right of self-determination should not be lost merely because an individual is unable to sense a violation of it, the court held that incompetent individuals retain a right to refuse treatment. It also held that such a right could be exercised by a surrogate decisionmaker using a “subjective” standard when there was clear evidence that the incompetent person would have exercised it. Where such evidence was lacking, the court held that an individual’s right could still be invoked in certain circumstances under objective “best interest” standards. Id., at 361-368, 486 A. 2d, at 1229-1233. Thus, if some trustworthy evidence existed that the individual would have wanted to terminate treatment, but not enough to clearly establish a person’s wishes for purposes of the subjective standard, and the burden of a prolonged life from the experience of pain and suffering markedly outweighed its satisfactions, treatment could be terminated under a “limited-objective” standard. Where no trustworthy evidence existed, and a person’s suffering would make the administration of life-sustaining treatment inhumane, a “pure-objective” standard could be used to terminate treatment. If none of these conditions obtained, the court held it was best to err in favor of preserving life. Id., at 364-368, 486 A. 2d, at 1231-1233.
The court also rejected certain categorical distinctions that had been drawn in prior refusal-of-treatment cases as lacking substance for decision purposes: the distinction between actively hastening death by terminating treatment and passively allowing a person to die of a disease; between treating individuals as an initial matter versus withdrawing treatment afterwards; between ordinary versus extraordinary treatment; and between treatment by artificial feeding versus other forms of life-sustaining medical procedures. Id., at 369-374, 486 A. 2d, at 1233-1237. As to the last item, the court acknowledged the “emotional significance” of food, but noted that feeding by implanted tubes is a “medical procedure] with inherent risks and possible side effects, instituted by skilled health-care providers to compensate for impaired physical functioning” which analytically was equivalent to artificial breathing using a respirator. Id., at 373, 486 A. 2d, at 1236.
In contrast to Conroy, the Court of Appeals of New York recently refused to accept less than the clearly expressed wishes of a patient before permitting the exercise of her right to refuse treatment by a surrogate decisionmaker. In re Westchester County Medical Center on behalf of O’Connor, 72 N. Y. 2d 517, 531 N. E. 2d 607 (1988) (O’Connor). There, the court, over the objection of the patient’s family members, granted an order to insert a feeding tube into a 77-year-old woman rendered incompetent as a result of several strokes. While continuing to recognize a common-law right to refuse treatment, the court rejected the substituted judgment approach for asserting it “because it is inconsistent with our fundamental commitment to the notion that no person or court should substitute its judgment as to what would be an acceptable quality of life for another. Consequently, we adhere to the view that, despite its pitfalls and inevitable uncertainties, the inquiry must always be narrowed to the patient’s expressed intent, with every effort made to minimize the opportunity for error.” Id., at 530, 531 N. E. 2d, at 613 (citation omitted). The court held that the record lacked the requisite clear and convincing evidence of the patient’s expressed intent to withhold life-sustaining treatment. Id., at 531-534, 531 N. E. 2d, at 613-615.
Other courts have found state statutory law relevant to the resolution of these issues. In Conservatorship of Drabick, 200 Cal. App. 3d 185, 245 Cal. Rptr. 840, cert. denied, 488 U. S. 958 (1988), the California Court of Appeal authorized the removal of a nasogastric feeding tube from a 44-year-old man who was in a persistent vegetative state as a result of an auto accident. Noting that the right to refuse treatment was grounded in both the common law and a constitutional right of privacy, the court held that a state probate statute authorized the patient’s conservator to order the withdrawal of life-sustaining treatment when such a decision was made in good faith based on medical advice and the conservatee’s best interests. While acknowledging that “to claim that [a patient’s] ‘right to choose’ survives incompetence is a legal fiction at best,” the court reasoned that the respect society accords to persons as individuals is not lost upon incompetence and is best preserved by allowing others “to make a decision that reflects [a patient’s] interests more closely than would a purely technological decision to do whatever is possible.” Id., at 208, 245 Cal. Rptr., at 854-855. See also In re Conservatorship of Torres, 357 N. W. 2d 332 (Minn. 1984) (Minnesota court had constitutional and statutory authority to authorize a conservator to order the removal of an incompetent individual’s respirator since in patient’s best interests).
In In re Estate of Longeway, 133 Ill. 2d 33, 549 N. E. 2d 292 (1989), the Supreme Court of Illinois considered whether a 76-year-old woman rendered incompetent from a series of strokes had a right to the discontinuance of artificial nutrition and hydration. Noting that the boundaries of a federal right of privacy were uncertain, the court found a right to refuse treatment in the doctrine of informed consent. Id., at 43-45, 549 N. E. 2d, at 296-297. The court further held that the State Probate Act impliedly authorized a guardian to exercise a ward’s right to refuse artificial sustenance in the event that the ward was terminally ill and irreversibly comatose. Id., at 45-47, 549 N. E. 2d, at 298. Declining to adopt a best interests standard for deciding when it would be appropriate to exercise a ward’s right because it “lets another make a determination of a patient’s quality of life,” the court opted instead for a substituted judgment standard. Id., at 49, 549 N. E. 2d, at 299. Finding the “expressed intent” standard utilized in O’Connor, supra, too rigid, the court noted that other clear and convincing evidence of the patient’s intent could be considered. 133 Ill. 2d, at 50-51, 549 N. E. 2d, at 300. The court also adopted the “consensus opinion [that] treats artificial nutrition and hydration as medical treatment.” Id., at 42, 549 N. E. 2d, at 296. Cf. McConnell v. Beverly Enterprises-Connecticut, Inc., 209 Conn. 692, 705, 553 A. 2d 596, 603 (1989) (right to withdraw artificial nutrition and hydration found in the Connecticut Removal of Life Support Systems Act, which “provides] functional guidelines for the exercise of the common law and constitutional rights of self-determination”; attending physician authorized to remove treatment after finding that patient is in a terminal condition, obtaining consent of family, and considering expressed wishes of patient).
As these cases demonstrate, the common-law doctrine of informed consent is viewed as generally encompassing the right of a competent individual to refuse medical treatment. Beyond that, these cases demonstrate both similarity and diversity in their approaches to decision of what all agree is a perplexing question with unusually strong moral and ethical overtones. State courts have available to them for decision a number of sources — state constitutions, statutes, and common law — which are not available to us. In this Court, the question is simply and starkly whether the United States Constitution prohibits Missouri from choosing the rule of decision which it did. This is the first case in which we have been squarely presented with the issue whether the United States Constitution grants what is in common parlance referred to as a “right to die.” We follow the judicious counsel of our decision in Twin City Bank v. Nebeker, 167 U. S. 196, 202 (1897), where we said that in deciding “a question of such magnitude and importance ... it is the [better] part of wisdom not to attempt, by any general statement, to cover every possible phase of the subject.”
The Fourteenth Amendment provides that no State shall “deprive any person of life, liberty, or property, without due process of law. ” The principle that a competent person has a constitutionally protected liberty interest in refusing unwanted medical treatment may be inferred from our prior decisions. In Jacobson v. Massachusetts, 197 U. S. 11, 24-30 (1905), for instance, the Court balanced an individual’s liberty interest in declining an unwanted smallpox vaccine against the State’s interest in preventing disease. Decisions prior to the incorporation of the Fourth Amendment into the Fourteenth Amendment analyzed searches and seizures involving the body under the Due Process Clause and were thought to implicate substantial liberty interests. See, e. g., Breithaupt v. Abram, 352 U. S. 432, 439 (1957) (“As against the right of an individual that his person be held inviolable . . . must be set the interests of society . . .”).
Just this Term, in the course of holding that a State’s procedures for administering antipsychotic medication to prisoners were sufficient to satisfy due process concerns, we recognized that prisoners possess “a significant liberty interest in avoiding the unwanted administration of antipsychotic drugs under the Due Process Clause of the Fourteenth Amendment.” Washington v. Harper, 494 U. S. 210, 221-222 (1990); see also id,., at 229 (“The forcible injection of medication into a nonconsenting person’s body represents a substantial interference with that person’s liberty”). Still other cases support the recognition of a general liberty interest in refusing medical treatment. Vitek v. Jones, 445 U. S. 480, 494 (1980) (transfer to mental hospital coupled with mandatory behavior modification treatment implicated liberty interests); Parham v. J. R., 442 U. S. 584, 600 (1979) (“[A] child, in common with adults, has a substantial liberty interest in not being confined unnecessarily for medical treatment”).
But determining that a person has a “liberty interest” under the Due Process Clause does not end the inquiry; “whether respondent’s constitutional rights have been violated must be determined by balancing his liberty interests against the relevant state interests.” Youngberg v. Romeo, 457 U. S. 307, 321 (1982). See also Mills v. Rogers, 457 U. S. 291, 299 (1982).
Petitioners insist that under the general holdings of our cases, the forced administration of life-sustaining medical treatment, and even of artificially delivered food and water essential to life, would implicate a competent person’s liberty interest. Although we think the logic of the cases discussed above would embrace such a liberty interest, the dramatic consequences involved in refusal of such treatment would inform the inquiry as. to whether the deprivation of that interest is constitutionally permissible. But for purposes of this case, we assume that the United States Constitution would grant a competent person a constitutionally protected right to refuse lifesaving hydration and nutrition.
Petitioners go on to assert that an incompetent person should possess the same right in this respect as is possessed by a competent person. They rely primarily on our decisions in Parham v. J. R., supra, and Youngberg v. Romeo, supra. In Parham, we held that a mentally disturbed minor child had a liberty interest in “not being confined unnecessarily for medical treatment,” 442 U. S., at 600, but we certainly did not intimate that such a minor child, after commitment, would have a liberty interest in refusing treatment. In Youngberg, we held that a seriously retarded adult had a liberty interest in safety and freedom from bodily restraint, 457 U. S., at 320. Youngberg, however, did not deal with decisions to administer or withhold medical treatment.
The difficulty with petitioners’ claim is that in a sense it begs the question: An incompetent person is not able to make an informed and voluntary choice to exercise a hypothetical right to refuse treatment or any other right. Such a “right” must be exercised for her, if at all, by some sort of surrogate. Here, Missouri has in effect recognized that under certain circumstances a surrogate may act for the patient in electing to have hydration and nutrition withdrawn in such a way as to cause death, but it has established a procedural safeguard to assure that the action of the surrogate conforms as best it may to the wishes expressed by the patient while competent. Missouri requires that evidence of the incompetent’s wishes as to the withdrawal of treatment be proved by clear and convincing evidence. The question, then, is whether the United States Constitution forbids the establishment of this procedural requirement by the State. We hold that it does not.
Whether or not Missouri’s clear and convincing evidence requirement comports with the United States Constitution depends in part on what interests the State may properly seek to protect in this situation. Missouri relies on its interest in the protection and preservation of human life, and there can be no gainsaying this interest. As a general matter, the States — indeed, all civilized nations — demonstrate their commitment to life by treating homicide as a serious crime. Moreover, the majority of States in this country have laws imposing criminal penalties on one who assists another to commit suicide. We do not think a State is required to remain neutral in the face of an informed and voluntary decision by a physically able adult to starve to death.
But in the context presented here, a State has more particular interests at stake. The choice between life and death is a deeply personal decision of obvious and overwhelming finality. We believe Missouri may legitimately seek to safeguard the personal element of this choice through the imposition of heightened evidentiary requirements. It cannot be disputed that the Due Process Clause protects an interest in life as well as an interest in refusing life-sustaining medical treatment. Not all incompetent patients will have loved ones available to serve as surrogate decisionmakers. And even where family members are present, “[t]here will, of course, be some unfortunate situations in which family members will not act to protect a patient.” In re Jobes, 108 N. J. 394, 419, 529 A. 2d 434, 447 (1987). A State is entitled to guard against potential abuses in such situations. Similarly, a State is entitled to consider that a judicial proceeding to make a determination regarding an incompetent’s wishes may very well not be an adversarial one, with the added guarantee of accurate factfinding that the adversary process brings with it. See Ohio v. Akron Center for Reproductive Health, post, at 515-516. Finally, we think a State may properly decline to make judgments about the “quality” of life that a particular individual may enjoy, and simply assert an unqualified interest in the preservation of human life to be weighed against the constitutionally protected interests of the individual.
In our view, Missouri has permissibly sought to advance these interests through the adoption of a “clear and convincing” standard of proof to govern such proceedings. “The function of a standard of proof, as that concept is embodied in the Due Process Clause and in the realm of factfinding, is to ‘instruct the factfinder concerning the degree of confidence our society thinks he should have in the correctness of factual conclusions for a particular type of adjudication.’” Addington v. Texas, 441 U. S. 418, 423 (1979) (quoting In re Winship, 397 U. S. 358, 370 (1970) (Harlan, J., concurring)). “This Court has mandated an intermediate standard of proof — ‘clear and convincing evidence’ — when the individual interests at stake in a state proceeding are both ‘particularly important’ and ‘more substantial than mere loss of money.’” Santosky v. Kramer, 455 U. S. 745, 756 (1982) (quoting Addington, supra, at 424). Thus, such a standard has been required in deportation proceedings, Woodby v. INS, 385 U. S. 276 (1966), in denaturalization proceedings, Schneiderman v. United States, 320 U. S. 118 (1943), in civil commitment proceedings, Addington, supra, and in proceedings for the termination of parental rights, Santosky, supra. " Further, this level of proof, “or an even higher one, has traditionally been imposed in cases involving allegations of civil fraud, and in a variety of other kinds of civil cases involving such issues as . . . lost wills, oral contracts to make bequests, and the like.” Woodby, supra, at 285, n. 18.
We think it self-evident that the interests at stake in the instant proceedings are more substantial, both on an individual and societal level, than those involved in a run-of-the-mine civil dispute. But not only does the standard of proof reflect the importance of a particular adjudication, it also serves as “a societal judgment about how the risk of error should be distributed between the litigants.” Santosky, supra, at 755; Addington, supra, at 423. The more stringent the burden of proof a party must bear, the more that party bears the risk of an erroneous decision. We believe that Missouri may permissibly place an increased risk of an erroneous decision on those seeking to terminate an incompetent individual’s life-sustaining treatment. An erroneous decision not to terminate results in a maintenance of the status quo; the possibility of subsequent developments such as advancements in medical science, the discovery of new evidence regarding the patient’s intent, changes in the law, or simply the unexpected death of the patient despite the administration of life-sustaining treatment at least create the potential that a wrong decision will eventually be corrected or its impact mitigated. An erroneous decision to withdraw life-sustaining treatment, however, is not susceptible of correction. In Santosky, one of the factors which led the Court to require proof by clear and convincing evidence in a proceeding to terminate parental rights was that a decision in such a case was final and irrevocable. Santosky, supra, at 759. The same must surely be said of the decision to discontinue hydration and nutrition of a patient such as Nancy Cru-zan, which all agree will result in her death.
It is also worth noting that most, if not all, States simply forbid oral testimony entirely in determining the wishes of parties in transactions which, while important, simply do not have the consequences that a decision to terminate a person’s life does. At common law and by statute in most States, the parol evidence rule prevents the variations of the terms of a written contract by oral testimony. The statute of frauds makes unenforceable oral contracts to leave property by will, and statutes regulating the making of wills universally require that those instruments be in writing. See 2 A. Corbin, Contracts §398, pp. 360-361 (1950); 2 W. Page, Law of Wills §§ 19.3-19.5, pp. 61-71 (1960). There is no doubt that statutes requiring wills to be in writing, and statutes of frauds which require that a contract to make a will be in writing, on occasion frustrate the effectuation of the intent of a particular decedent, just as Missouri’s requirement of proof in this case may have frustrated the effectuation of the not-fully-expressed desires of Nancy Cruzan. But the Constitution does not require general rules to work faultlessly; no general rule can.
In sum, we conclude that a State may apply a clear and convincing evidence standard in proceedings where a guardian seeks to discontinue nutrition and hydration of a person diagnosed to be in a persistent vegetative state. We note that many courts which have adopted some sort of substituted judgment procedure in situations like this, whether they limit consideration of evidence to the prior expressed wishes of the incompetent individual, or whether they allow more general proof of what the individual’s decision would have been, require a clear and convincing standard of proof for such evidence. See, e. g., Longeway, 133 Ill. 2d, at 50-51, 549 N. E. 2d, at 300; McConnell, 209 Conn., at 707-710, 553 A. 2d, at 604-605; O’Connor, 72 N. Y. 2d, at 529-530, 531 N. E. 2d, at 613; In re Gardner, 534 A. 2d 947, 952-953 (Me. 1987); In re Jobes, 108 N. J., at 412-413, 529 A. 2d, at 443; Leach v. Akron General Medical Center, 68 Ohio Misc. 1, 11, 426 N. E. 2d 809, 815 (1980).
The Supreme Court of Missouri held that in this case the testimony adduced at trial did not amount to clear and convincing proof of the patient’s desire to have hydration and nutrition withdrawn. In so doing, it reversed a decision of the Missouri trial court which had found that the evidence “suggested]” Nancy Cruzan would not have desired to continue such measures, App. to Pet. for Cert. A98, but which had not adopted the standard of “clear and convincing evidence” enunciated by the Supreme Court. The testimony adduced at trial consisted primarily of Nancy Cruzan’s statements made to a housemate about a year before her accident that she would not want to live should she face life as a “vegetable,” and other observations to the same effect. The observations did not deal in terms with withdrawal of medical treatment or of hydration and nutrition. We cannot say that the Supreme Court of Missouri committed constitutional error in reaching the conclusion that it did.
Petitioners alternatively contend that Missouri must accept the “substituted judgment” of close family members even in the absence of substantial proof that their views re-fleet the views of the patient. They rely primarily upon our decisions in Michael H. v. Gerald D., 491 U. S. 110 (1989), and Parham v. J. R., 442 U. S. 584 (1979). But we do not think these cases support their claim. In Michael H., we upheld the constitutionality of California’s favored treatment of traditional family relationships; such a holding may not be turned around into a constitutional requirement that a State must recognize the primacy of those relationships in a situation like this. And in Parham, where the patient was a minor, we also upheld the constitutionality of a state scheme in which parents made certain decisions for mentally ill minors. Here again petitioners would seek to turn a decision which allowed a State to rely on family decisionmaking into a constitutional requirement that the State recognize such de-cisionmaking. But constitutional law does not work that way.
No doubt is engendered by anything in this record but that Nancy Cruzan’s mother and father are loving and caring parents. If the State were required by the United States Com stitution to repose a right of “substituted judgment” with anyone, the Cruzans would surely qualify. But we do not think the Due Process Clause requires the State to repose judgment on these matters with anyone but the patient herself. Close family members may have a strong feeling — a feeling not at all ignoble or unworthy, but not entirely disinterested, either — that they do not wish to witness the continuation of the life of a loved one which they regard as hopeless, meaningless, and even degrading. But there is no automatic assurance that the view of close family members will necessarily be the same as the patient’s would have been had she been confronted with the prospect of her situation while competent. All of the reasons previously discussed for allowing Missouri to require clear and convincing evidence of the patient’s wishes lead us to conclude that the State may choose to defer only to those wishes, rather than confide the decision to close family members.
The judgment of the Supreme Court of Missouri is
Affirmed.
The State Supreme Court, adopting much of the trial court’s findings, described Nancy Cruzan’s medical condition as follows:
“. . . (1) [H]er respiration and circulation are not artificially maintained and are within the normal limits of a thirty-year-old female; (2) she is oblivious to her environment except for reflexive responses to sound and perhaps painful stimuli; (3) she suffered anoxia of the brain resulting in a massive enlargement of the ventricles filling with cerebrospinal fluid in the area where the brain has degenerated and [her] cerebral cortical atrophy is irreversible, permanent, progressive and ongoing; (4) her highest cognitive brain function is exhibited by her grimacing perhaps in recognition of ordinarily painful stimuli, indicating the experience of pain and apparent response to sound; (5) she is a spastic quadriplegic; (6) her four extremities are contracted with irreversible muscular and tendon damage to all extremities; (7) she has no cognitive or reflexive ability to swallow food or water to maintain her daily essential needs and . . . she will never recover her ability to swallow sufficient [sic] to satisfy her needs. In sum, Nancy is diagnosed as in a persistent vegetative state. She is not dead. She is not terminally ill. Medical experts testified that she could live another thirty years.” Cruzan v. Harmon, 760 S. W. 2d 408, 411 (Mo. 1989) (en banc) (quotations omitted; footnote omitted).
In observing that Cruzan was not dead, the court referred to the following Missouri statute:
“For all legal purposes, the occurrence of human death shall be determined in accordance with the usual and customary standards of medical practice, provided that death shall not be determined to have occurred unless the following minimal conditions have been met:
“(1) When respiration and circulation are not artificially maintained, there is an irreversible cessation of spontaneous respiration and circulation; or
“(2) When respiration and circulation are artificially maintained, and there is total and irreversible cessation of all brain function, including the brain stem and that such determination is made by a licensed physician.” Mo. Rev. Stat. § 194.005 (1986).
Since Cruzan’s respiration and circulation were not being artificially maintained, she obviously fit within the first proviso of the statute.
Dr. Fred Plum, the creator of the term “persistent vegetative state” and a renowned expert on the subject, has described the “vegetative state” in the following terms:
“ ‘Vegetative state describes a body which is functioning entirely in terms of its internal controls. It maintains temperature. It maintains heart beat and pulmonary ventilation. It maintains digestive activity. It maintains reflex activity of muscles and nerves for low level conditioned responses. But there is no behavioral evidence of either self-awareness or awareness of the surroundings in a learned manner.’” In re Jobes, 108 N. J. 394, 403, 529 A. 2d 434, 438 (1987).
See also Brief for American Medical Association et al. as Amici Curiae 6 (“The persistent vegetative state can best be understood as one of the conditions in which patients have suffered a loss of consciousness”).
See generally Karnezis, Patient’s Right to Refuse Treatment Allegedly Necessary to Sustain Life, 93 A. L. R. 3d 67 (1979) (collecting cases); Cantor, A Patient’s Decision to Decline Life-Saving Medical Treatment: Bodily Integrity Versus the Preservation of Life, 26 Rutgers L. Rev. 228, 229, and n. 5 (1973) (noting paucity of cases).
See Chapman, The Uniform Rights of the Terminally Ill Act: Too Little, Too Late?, 42 Ark. L. Rev. 319, 324, n. 15 (1989); see also F. Rozovsky, Consent to Treatment, A Practical Guide 415-423 (1984).
In a later trilogy of cases, the New Jersey Supreme Court stressed that the analytic framework adopted in Conroy was limited to elderly, incompetent patients with shortened life expectancies, and established alternative approaches to deal with a different set of situations. See In re Farrell, 108 N. J. 335, 529 A. 2d 404 (1987) (37-year-old competent mother with terminal illness had right to removal of respirator based on common law and constitutional principles which overrode competing state interests); In re Peter, 108 N. J. 365, 529 A. 2d 419 (1987) (65-year-old woman in persistent vegetative state had right to removal of nasogastric feeding tube — under Conroy subjective test, power of attorney and hearsay testimony constituted clear and convincing proof of patient’s intent to have treatment withdrawn); In re Jobes, 108 N. J. 394, 529 A. 2d 434 (1987) (31-year-old woman in persistent vegetative state entitled to removal of jejunostomy feeding tube — even though hearsay testimony regarding patient’s intent insufficient to meet clear and convincing standard of proof, under Quinlan, family or close friends entitled to make a substituted judgment for patient).
The Drabick court drew support for its analysis from earlier, influential decisions rendered by California Courts of Appeal. See Bouvia v. Su perior Court, 179 Cal. App. 3d 1127, 225 Cal. Rptr. 297 (1986) (competent 28-year-old quadriplegic had right to removal of nasogastric feeding tube inserted against her will); Bartling v. Superior Court, 163 Cal. App. 3d 186, 209 Cal. Rptr. 220 (1984) (competent 70-year-old, seriously ill man had right to the removal of respirator); Barber v. Superior Court, 147 Cal. App. 3d 1006, 195 Cal. Rptr. 484 (1983) (physicians could not be prosecuted for homicide on account of removing respirator and intravenous feeding tubes of patient in persistent vegetative state).
Besides the Missouri Supreme Court in Cruzan and the courts in McConnell, Longeway, Drabick, Bolivia, Barber, O’Connor, Conroy, Jobes, and Peter, appellate courts of at least four other States and one Federal District Court have specifically considered and discussed the issue of withholding or withdrawing artificial nutrition and hydration from incompetent individuals. See Gray v. Romeo, 697 F. Supp. 580 (RI 1988); In re Gardner, 534 A. 2d 947 (Me. 1987); In re Grant, 109 Wash. 2d 545, 747 P. 2d 445 (1987); Brophy v. New England Sinai Hospital, Inc., 398 Mass. 417, 497 N. E. 2d 626 (1986); Corbett v. D'Alessandro, 487 So. 2d 368 (Fla. App. 1986). All of these courts permitted or would permit the termination of such measures based on rights grounded in the common law, or in the State or Federal Constitution.
Although many state courts have held that a right to refuse treatment is encompassed by a generalized constitutional right of privacy, we have never so held. We believe this issue is more properly analyzed in terms of a Fourteenth Amendment liberty interest. See Bowers v. Hardwick, 478 U. S. 186, 194-195 (1986).
See Smith, All’s Well That Ends Well: Toward a Policy of Assisted Rational Suicide or Merely Enlightened Self-Determination?, 22 U. C. D. L. Rev. 275, 290-291, and n. 106 (1989) (compiling statutes).
Since Cruzan was a patient at a state hospital when this litigation commenced, the State has been involved as an adversary from the beginning. However, it can be expected that many disputes of this type will arise in private institutions, where a guardian ad litem or similar party will have been appointed as the sole representative of the incompetent individual in the litigation. In such cases, a guardian may act in entire good faith, and yet not maintain a position truly adversarial to that of the family. Indeed, as noted by the court below, “[tlhe guardian ad litem [in this case] finds himself in the predicament of believing that it is in Nancy’s 'best interest to have the tube feeding discontinued,’ but ‘feeling that an appeal should be made because our responsibility to her as attorneys and guardians ad litem was to pursue this matter to the highest court in the state in view of the fact that this is a case of first impression in the State of Missouri."’ 760 S. W. 2d, at 410, n. 1. Cruzan’s guardian ad litem has also filed a brief in this Court urging reversal of the Missouri Supreme Court's decision. None of this is intended to suggest that the guardian acted the least bit improperly in this proceeding. It is only meant to illustrate the limits which may obtain on the adversarial nature of this type of litigation.
We recognize that these cases involved instances where the government sought to take action against an individual. See Price Waterhouse v. Hopkins, 490 U. S. 228, 253 (1989) (plurality opinion). Here, by contrast, the government seeks to protect the interests of an individual, as well as its own institutional interests, in life. We do not see any reason why important individual interests should be afforded less protection simply because the government finds itself in the position of defending them. “[W]e find it significant that . . . the defendant rather than the plaintiff” seeks the clear and convincing standard of proof — “suggesting that this standard ordinarily serves as a shield rather than ... a sword.” Id., at 253. That it is the government that has picked up the shield should be of no moment.
The clear and convincing standard of proof has been variously defined in this context as “proof sufficient to persuade the trier of fact that the patient held a firm and settled commitment to the termination of life supports under the circumstances like those presented," In re Westchester County Medical Center on behalf of O’Connor, 72 N. Y. 2d 517, 531, 531 N. E. 2d 607, 613 (1988) (O'Connor), and as evidence which “produces in the mind of the trier of fact a firm belief or conviction as to the truth of the allegations sought to be established, evidence so clear, direct and weighty and convincing as to enable [the factfinder] to come to a clear conviction, without hesitancy, of the truth of the precise facts in issue." In re Jobes. 108 N. J., at 407-408, 529 A. 2d, at 441 (quotation omitted). In both of these eases the evidence of the patient’s intent to refuse medical treatment was arguably stronger than that presented here. The New York Court of Appeals and the Supreme Court of New Jersey, respectively, held that the proof failed to meet a clear and convincing threshold. See O'Connor, supra, at 526-534, 531 N. E. 2d, at 610-615; Jobes, supra, at 442-443.
We are not faced in this case with the question whether a State might be required to defer to the decision of a surrogate if competent and probative evidence established that the patient herself had expressed a desire that the decision to terminate life-sustaining treatment be made for her by that individual.
Petitioners also adumbrate in their brief a claim based on the Equal Protection Clause of the Fourteenth Amendment to the effect that Missouri has impermissibly treated incompetent patients differently from competent ones, citing the statement in Cleburne v. Cleburne Living Center. Inc., 473 U. S. 432, 439 (1985), that the Clause is “essentially a direction that all persons similarly situated should be treated alike." The differences between the choice made by a competent person to refuse medical treatment, and the choice made for an incompetent person by someone else to refuse medical treatment, are so obviously different that the State is warranted in establishing rigorous procedures for the latter class of cases which do not apply to the former class.