Substantive Due Process: The Thinning Legal Line

3 min readJun 25, 2022


Receiving scant attention in the Dobbs decision overturning Roe v. Wade is a concurrence by Justice Thomas that threatens all we regard as Constitutional rights. Thomas writes that:

“in future cases, we should reconsider all of this Court’s substantive due process precedents, including Griswold, Lawrence, and Obergefell. Because any substantive due process decision is “demonstrably erroneous . . . Accordingly, we should eliminate it from our jurisprudence at the earliest opportunity.”

To understand the sweeping breadth of what Thomas is suggesting requires understanding what substantive due process is and where it comes from. It comes from 14th Amendment’s words: “nor shall any state deprive any person of life, liberty or property without due process of law.” Substantive due process focuses on the word “liberty” in that provision.

Why is it was it even necessary to include these words in the 14th Amendment when nearly the same words are found in the 5th Amendment? Because the 5th, as with all of the Bill of Rights, restricted only the Federal government, not states. The 14th Amendment, for the first time, limited the power of states in this regard.

Substantive due process takes the word “liberty” in the due process clause of the 14th Amendment to mean that states cannot deprive persons of rights deemed “fundamental” or “basic.” The debate thus becomes what rights are deemed fundamental or basic? And, how is that decided?

The first use of substantive due process looked to rights otherwise granted in the Constitution’s Bill of Rights. Some provisions in the Bill of Rights were deemed fundamental, and thus “incorporated” into the due process clause of the 14th Amendment. It is only through this substantive due process that states today cannot restrict speech, or religion, conduct unreasonable searches, or for that matter infringe on gun rights in the 2d Amendment.

Notably, not all the Bill of Rights were so incorporated. The process is called “selective incorporation” because only those deemed as fundamental rights are protected. The rights to a grand jury in the 5th Amendment, and to jury trial in civil cases in the 7th, have never been incorporated as they are not deemed fundamental rights.

If “any substantive due process decision is demonstrably erroneous,” as Thomas claims, then all of this gone. None of the Bill of Rights applies against states and states are once again free to restrict speech, religion, and gun rights, etc. Only substantive due process prevents that. Yet that is what Thomas is suggesting in saying any substantive due process is “demonstrably erroneous.”

Of course Thomas says the courts should first go after rights deemed fundamental but not specifically mentioned in the Constitution. The right to birth control, that states can’t criminalize gay sex or ban gay marriage. Those too are rooted in substantive due process, by what “liberty” means. There is no clear basis for going after them first, but that is what Thomas suggests.

Thomas’ own marriage is partially rooted in substantive due process where interracial marriage was not deemed a fundamental right until 1967. A time Thomas should remember well enough, he was 19 and old enough to marry.

Substantive Due Process Makes This Marriage Possible

Thomas makes clear he knows what he is suggesting. He argues that perhaps some rights lost by eliminating substantive due process might, maybe, possibly, be found as within the “privileges or immunities of citizens of the United States” also articulated in the 14th Amendment. However, he is far from actually advocating that, stating, “important antecedent questions” would have to be answered first.

Only substantive due process protects your free speech, religion, gun rights, and most of the Bill of Rights from state intrusion. Only substantive due process protects your right to birth control, to marry the person you love, and even from compulsory sterilization by the state. With an increasingly radicalized Supreme Court, all of that is in danger.

For the court to struggle with defining what is, and is not, a fundamental right is understandable. But to completely abandon the doctrine of substantive due process is to destroy the basis by which Americans are protected from state attacks on their fundamental rights.




Retired lawyer & Army vet in The Villages of Florida. Lifelong: Republican (pre-Trump), Constitution buff, science nerd & dog lover. Twitter: @KeithDB80