In this essay, James R. Stoner gives an introduction to natural law in the common law tradition. The common law is the body of customary, unwritten law of England, especially that which was derived over centuries from the rulings of court cases (not by legislative acts). Much of it was imported into the American legal system. The parts of common law that are most invoked in the United States are the procedural rules for administering justice, also called “due process”: trial by a jury of twelve peers, the right not to witness against oneself, and many others. Many of these procedures are required explicitly by the U.S. Constitution.

The common law tradition reflects the natural law tradition in three ways: it privileges individual liberty and the assent of the community and minimizes the role of the central political authority; its appeals courts use reason to relate novel cases to historical precedent; and it can limit or void written positive law if the law contradicts reason outright. (In the United States this last aspect gave rise to the doctrine of “judicial review.”)

In the twentieth century, when skepticism grew about appeals to reason and natural law, American legal theorists began to view common law as simply “judge-made” positive law, little different from laws created by legislatures.