Constitutional protection of the woman's decision to terminate her pregnancy derives from the Due Process Clause of the Fourteenth Amendment. It declares that no State shall 'deprive any person of life, liberty, or property, without due process of law.' The controlling word in the cases before us is 'liberty.' Although a literal reading of the Clause might suggest that it governs only the procedures by which a State may deprive persons of liberty, for at least 105 years, since Mugler v. Kansas, 123 U. S. 623, 660-661 (1887), the Clause has been understood to contain a substantive component as well, one 'barring certain government actions regardless of the fairness of the procedures used to implement them.' Daniels v. Williams, 474 U. S. 327, 331 (1986). As Justice Brandeis (joined by Justice Holmes) observed, '[d]espite arguments to the contrary which had seemed to me persuasive, it is settled that the due process clause of the Fourteenth Amendment applies to matters of substantive law as well as to matters of procedure. Thus all fundamental rights comprised within the term liberty are protected by the Federal Constitution from invasion by the States.' Whitney v. California, 274 U. S. 357, ...