Substantive Due Process

Substantive due process is a judicial doctrine in United States constitutional law under which courts read the Due Process Clauses of the Fifth Amendment (applicable to the federal government) and the Fourteenth Amendment (applicable to the states) as protecting not only fair procedures but also certain substantive rights that the government cannot infringe without sufficient justification.

The doctrine distinguishes between procedural due process—what process is owed before the government deprives a person of life, liberty, or property—and substantive due process, which asks whether the government has adequate justification for the deprivation at all. Where a "fundamental right" is implicated, courts apply strict scrutiny, requiring that the law be narrowly tailored to serve a compelling state interest. Otherwise, courts typically apply rational basis review.

Key phases in the doctrine include:

• The Lochner era (roughly 1897–1937), in which the Supreme Court used substantive due process to strike down economic regulations, most famously in Lochner v. New York (1905), which invalidated a New York maximum-hours law for bakers. This approach was largely abandoned after West Coast Hotel Co. v. Parrish (1937).
• The modern era, in which the doctrine has been used to recognize unenumerated personal rights. Examples include the right to marry (Loving v. Virginia, 1967; Obergefell v. Hodges, 2015), the right to use contraception (Griswold v. Connecticut, 1965), and parental rights (Pierce v. Society of Sisters, 1925).
• The Court's framework in Washington v. Glucksberg (1997) asks whether an asserted right is "deeply rooted in this Nation's history and tradition."
• In Dobbs v. Jackson Women's Health Organization (2022), the Court overruled Roe v. Wade (1973) and Planned Parenthood v. Casey (1992), narrowing the doctrine's reach regarding abortion.

The doctrine remains contested: critics argue it lacks textual grounding, while defenders see it as essential to protecting unenumerated liberties.