Common Law
Common law refers to legal rules drawn from judicial decisions rather than from statutes or a constitution. In a diversity case, Erie Railroad Co. v. Tompkins requires a federal court to apply the relevant state’s law, including law declared by the state’s highest court, rather than make general federal common law.
Common law refers to legal rules drawn from judicial decisions rather than from statutes or a constitution. In a diversity case, Erie Railroad Co. v. Tompkins requires a federal court to apply the relevant state’s law, including law declared by the state’s highest court, rather than make general federal common law.
Example: In Erie Railroad Co. v. Tompkins (1938), the Supreme Court held that a federal court hearing a diversity case about an injury in Pennsylvania could not decide the applicable state-law issue as general law; it had to apply Pennsylvania law.
Common misconception: Common law has not been entirely replaced by statutes. The Supreme Court’s Erie decision applied unwritten state law, and the Constitution Annotated describes long-established judge-made doctrines and recognizes limited areas of federal common law.
Sources: Constitution Annotated, Substantive Claims and Defenses in Federal Question Cases; Erie Railroad Co. v. Tompkins, 304 U.S. 64 (1938); Constitution Annotated, Common Law Doctrines