Liberty finds no refuge in a jurisprudence of doubt. Yet, 19 years after our holding that the Constitution protects a woman's right to terminate her pregnancy in its early stages, Roe v. Wade, 410 U.S. 113 (1973), that definition of liberty is still questioned. . . .
Men and women of good conscience can disagree, and we suppose some always shall disagree, about the profound moral and spiritual implications of terminating a pregnancy, even in its earliest stage. Some of us as individuals find abortion offensive to our most basic principles of morality, but that cannot control our decision. Our obligation is to define the liberty of all, not to mandate our own moral code. The underlying constitutional issue is whether the State can resolve these philosophic questions in such a definitive way that a woman lacks all choice in the matter, except perhaps [505 U.S. 833, 851] in those rare circumstances in which the pregnancy is itself a danger to her own life or health, or is the result of rape or incest.
It is conventional constitutional doctrine that, where reasonable people disagree, the government can adopt one position or the other. See, e.g., Ferguson v. Skrupa, 372 U.S. 726 (1963); Williamson v. Lee Optical of Okla., Inc., 348 U.S. 483 (1955). That theorem, however, assumes a state of affairs in which the choice does not intrude upon a protected liberty. Thus, while some people might disagree about whether or not the flag should be saluted, or disagree about the proposition that it may not be defiled, we have ruled that a State may not compel or enforce one view or the other. See West Virginia Bd. of Ed. v. Barnette, 319 U.S. 624 (1943); Texas v. Johnson, 491 U.S. 397 (1989).
Our law affords constitutional protection to personal decisions relating to marriage, procreation, contraception, family relationships, child rearing, and education. Carey v. Population Services International, 431 U.S., at 685 . Our cases recognize the right of the individual, married or single, to be free from unwarranted governmental intrusion into matters so fundamentally affecting a person as the decision whether to bear or beget a child. Eisenstadt v. Baird, supra, 405 U.S., at 453 (emphasis in original). Our precedents "have respected the private realm of family life which the state cannot enter." Prince v. Massachusetts, 321 U.S. 158, 166 (1944). These matters, involving the most intimate and personal choices a person may make in a lifetime, choices central to personal dignity and autonomy, are central to the liberty protected by the Fourteenth Amendment. At the heart of liberty is the right to define one's own concept of existence, of meaning, of the universe, and of the mystery of human life. Beliefs about these matters could not define the attributes of personhood were they formed under compulsion of the State. [505 U.S. 833, 852]
These considerations begin our analysis of the woman's interest in terminating her pregnancy, but cannot end it, for this reason: though the abortion decision may originate within the zone of conscience and belief, it is more than a philosophic exercise. Abortion is a unique act. It is an act fraught with consequences for others: for the woman who must live with the implications of her decision; for the persons who perform and assist in the procedure; for the spouse, family, and society which must confront the knowledge that these procedures exist, procedures some deem nothing short of an act of violence against innocent human life; and, depending on one's beliefs, for the life or potential life that is aborted. Though abortion is conduct, it does not follow that the State is entitled to proscribe it in all instances. That is because the liberty of the woman is at stake in a sense unique to the human condition, and so, unique to the law. The mother who carries a child to full term is subject to anxieties, to physical constraints, to pain that only she must bear. That these sacrifices have from the beginning of the human race been endured by woman with a pride that ennobles her in the eyes of others and gives to the infant a bond of love cannot alone be grounds for the State to insist she make the sacrifice. Her suffering is too intimate and personal for the State to insist, without more, upon its own vision of the woman's role, however dominant that vision has been in the course of our history and our culture. The destiny of the woman must be shaped to a large extent on her own conception of her spiritual imperatives and her place in society.
It should be recognized, moreover, that in some critical respects, the abortion decision is of the same character as the decision to use contraception, to which Griswold v. Connecticut, Eisenstadt v. Baird, and Carey v. Population Services International afford constitutional protection. We have no doubt as to the correctness of those decisions. They support [505 U.S. 833, 853] the reasoning in Roe relating to the woman's liberty, because they involve personal decisions concerning not only the meaning of procreation but also human responsibility and respect for it. As with abortion, reasonable people will have differences of opinion about these matters. One view is based on such reverence for the wonder of creation that any pregnancy ought to be welcomed and carried to full term, no matter how difficult it will be to provide for the child and ensure its wellbeing. Another is that the inability to provide for the nurture and care of the infant is a cruelty to the child and an anguish to the parent. These are intimate views with infinite variations, and their deep, personal character underlay our decisions in Griswold, Eisenstadt, and Carey. The same concerns are present when the woman confronts the reality that, perhaps despite her attempts to avoid it, she has become pregnant. . . .
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The inquiry into reliance counts the cost of a rule's repudiation as it would fall on those who have relied reasonably on the rule's continued application. . . .
To eliminate the issue of reliance that easily, however, one would need to limit cognizable reliance to specific instances of sexual activity. But to do this would be simply to refuse to face the fact that, for two decades of economic and social developments, people have organized intimate relationships and made choices that define their views of themselves and their places in society, in reliance on the availability of abortion in the event that contraception should fail. The ability of women to participate equally in the economic and social life of the Nation has been facilitated by their ability to control their reproductive lives.