Common law

Law generated from court cases and judicial decisions.


Common law, or judge-made law, is generated from a succession of judicial decisions or precedents. In common-law systems, courts are bound by the rule called stare decisis, or “let the precedent stand.” In the United States, common law is distinguished from equity law, which is based on reasoning about what is fair or equitable. It also differs from law based on statutes enacted by legislatures.

The Supreme Court building, Washington, D.C.

(Library of Congress)

Common-law systems are contrasted with civil-law systems found on the continent of Europe and elsewhere, which are based on legal codes. Some of these systems are based on the Code Civil (“civil law”) drafted in Napoleonic France, derived partially from Roman lawRoman law. By contrast, the common-law system was developed in England and brought to the American colonies. By 1776 the colonial courts used common law as a matter of course. After the American Revolution, decisions made in U.S. courts added to the body of common law.

The Supreme Court is a common-law court. Its decisions are the basis of constitutional lawConstitutional law and it generally adheres, except when changing circumstances warrant creation of new rules, to stare decisis. When government under the Constitution began in 1789, questions arose as to whether federal courts had jurisdiction over common law cases. The question also arose as to whether federal cases would themselves become a kind of common law in civil or criminal cases. The Court’s decisions regarding these questions had far-reaching consequences.

In United States v. Hudson and Goodwin[case]Hudson and Goodwin, United States v.[Hudson and Goodwin, United States v.] (1812), the Court ruled that no federal court could exercise common-law jurisdiction in criminal cases. It therefore denied the existence of a federal common law of crimes. Whether a federal common law of civil cases exists, however, was another matter. In 1842 in Swift v. Tyson[case]Swift v. Tyson[Swift v. Tyson], the Court ruled that there is federal common law in commercial cases. This ruling prevailed for nearly a century; then the Court, departing from stare decisis, reversed itself, ruling in Erie Railroad Co. v. Tompkins[case]Erie Railroad Co. v. Tompkins[Erie Railroad Co. v. Tompkins] (1938) that one of its own decisions Swift was unconstitutional. Speaking for the majority, Justice Louis D. Brandeis wrote: “There is no federal common law.” Nevertheless, this ruling did not completely eliminate the idea of federal common law, though today it is limited to specialized subjects.

The common-law process of following precedent in making decisions has allowed the federal judiciary to assume the position it holds in the U.S. constitutional plan. When Chief Justice John Marshall rendered the key decision in Marbury v. Madison[case]Marbury v. Madison[Marbury v. Madison] (1803) that established the federal courts’ power to declare laws void, he was following the common law obligation to apply all relevant law. Because of the force of precedent in common law procedure, the Court’s action in Marbury has reverberated through two centuries of legal tradition, helping to shape the theory and practice of U.S. government.



Further Reading

  • Farnsworth, E. Allan. An Introduction to the Legal System of the United States. 3d ed. Dobbs Ferry, N.Y.: Oceana Publications, 1996.
  • Friedman, Lawrence M. A History of American Law. 3d ed. New York: Simon & Schuster, 2005.
  • Hale, M., and C. Gray. The History of the Common Law in England. Chicago: University of Chicago, 2002.
  • Plucknett, Theodore Frank Thomas. A Concise History of the Common Law. 5th ed. Union, N.J.: Lawbook Exchange, 2001.
  • Schweber, Howard. The Creation of American Common Law, 1850-1880: Technology, Politics, and the Construction of Citizenship. New York: Cambridge University Press, 2004.



British background to U.S. judiciary

Civil law

Common law, federal

Constitutional law

Erie Railroad Co. v. Tompkins

Hudson and Goodwin, United States v.

Marbury v. Madison

Roman law

Rule of law

Swift v. Tyson