Most of us have long taken for granted the promise of our Constitution that certain core liberties—including the freedoms of speech, press, and religion—cannot be abridged by the states or by the federal government without extraordinary justification. A point easily forgotten is that it was not always so—that, for nearly the first eighty years of our Constitution’s history, the Bill of Rights protected these vital liberties only from interference by the federal government. The degree to which the states were obliged to respect the civil liberties of their own residents was largely a matter for the states themselves to decide. One need only recall the history of slavery to recognize how hollow is a guarantee of liberty that binds only half the government.
Enacted in the wake of the Civil War, the Fourteenth Amendment radically changed this basic pattern, imposing strong, federally enforceable limits on the actions of states and their subdivisions. The Fourteenth Amendment decreed that states may neither deprive persons of life, liberty, or property without due process of law nor deny persons the equal protection of the laws. Relying primarily on the first of these prohibitions—the Due Process Clause—the Supreme Court has for decades read the Fourteenth Amendment’s restrictions on the states as “incorporating” many of the guarantees the Bill of Rights secured against the federal government in 1791. Thus today it is understood that states, not just the federal government, are indirectly bound by the First Amendment’s command that “Congress shall make no law…abridging the freedom of speech.”
As Justice Cardozo explained in 1937, the Supreme Court’s practice of reading the Fourteenth Amendment to incorporate certain protections derived from the Bill of Rights “had its source in the belief that neither liberty nor justice would exist if [those rights] were sacrificed.” as Cardozo put it—the Fourteenth Amendment’s mandate that no state may deprive any person of liberty without due process of law has been construed to mean that certain deprivations of those rights are forbidden, whatever “process” might be employed in bringing about those deprivations. Some have found this to be an unnatural reading of the amendment’s words, which seem to suggest that government may deprive persons of any imaginable sort of liberty, provided it uses appropriate legal process. But the Court has adhered to this reading. The result is that the Due Process Clause of the Fourteenth Amendment has become the chief protector of “substantive liberties”—such as the freedoms of speech, press, and religion—against adverse action by the states.
The doctrine that the Due Process Clause protects substantive liberties has acquired a peculiar name in legal circles: “substantive due process.” Burdened with a label that is itself an oxymoron, the concept has been an easy target for ridicule. Professor John Hart Ely has compared “substantive due process” to “green pastel redness …