"Justice O'CONNOR, Justice KENNEDY, and Justice SOUTER announced the judgment of the Court and delivered the opinion of the Court with respect to Parts I, II, III, V-A, V-C, and VI, an opinion with respect to Part V-E, in which Justice STEVENS joins, and an opinion with respect to Parts IV, V-B, and V-D. 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, 93 S.Ct. 705, 35 L.Ed.2d 147 (1973), that definition of liberty is still questioned. Joining the respondents as amicus curiae, the United States, as it has done in five other cases in the last decade, again asks us to overrule Roe. See Brief for Respondents 104-117; Brief for United States as Amicus Curiae 8."