"Stare decisis is a cornerstone of our legal system, but it has less power in constitutional cases, where, save for constitutional amendments, this Court is the only body able to make needed changes. See United States v. Scott, 437 U. S. 82, 437 U. S. 101 (1978). We have not refrained from reconsideration of a prior construction of the Constitution that has proved "unsound in principle and unworkable in practice." Garcia v. San Antonio Metropolitan Transit Authority, 469 U. S. 528, 469 U. S. 546 (1985); see Solorio v. United States, 483 U. S. 435, 483 U. S. 448-450 (1987); Erie R. Co. v. Tompkins, 304 U. S. 64, 304 U. S. 74-78 (1938). We think the Roe trimester framework falls into that category. In the first place, the rigid Roe framework is hardly consistent with the notion of a Constitution cast in general terms, as ours is, and usually speaking in general principles, as ours does. The key elements of the Roe framework -- trimesters and viability -- are not found in the text of the Constitution, or in any place else one would expect to find a constitutional principle. Since the bounds of the inquiry are essentially indeterminate, the result has been a web of legal rules that have become increasingly intricate, resembling a code of regulations rather than a body of constitutional doctrine. [Footnote 15] AS JUSTICE WHITE has put it, the trimester framework has left this Court to serve as the country's "ex officio medical board with powers to approve or disapprove medical and operative practices and standards throughout the United States." Planned Parenthood of Central Mo. v. Danforth, 428 U.S. at 428 U. S. 99 (opinion concurring in part and dissenting in part). Cf. Garcia, supra, at 469 U. S. 547. In the second place, we do not see why the State's interest in protecting potential human life should come into existence only at the point of viability, and that there should therefore be a rigid line allowing state regulation after viability but prohibiting it before viability. The dissenters in Thornburgh, writing in the context of the Roe trimester analysis, would have recognized this fact by positing against the "fundamental right" recognized in Roe the State's "compelling interest" in protecting potential human life throughout pregnancy. "[T]he State's interest, if compelling after viability, is equally compelling before viability." Thornburgh, 476 U.S. at 476 U. S. 795 (WHITE, J., dissenting); see id. at 476 U. S. 828 (O'CONNOR, J., dissenting) ("State has compelling interests in ensuring maternal health and in protecting potential human life, and these interests exist throughout pregnancy'") (citation omitted)."