28 U.S.C. § 1652
Section 1652 · State laws as rules of decision
Amended 1 time on record
Applied in 569 court decisions — leading case Pennhurst State School and Hospital v. Halderman (1984)
Most recently applied in EOG Resources, Inc. v. Lucky Land Management, LLC (April 2025)
Applied most in the Ninth Circuit Circuit (29 decisions)
Cases citing this section usually also cite 28 U.S.C. § 1332 · 42 U.S.C. § 1983 · 28 U.S.C. § 1331
How often courts cite this section
Court decisions citing this, by year.Markers show enactment, consequential amendments, and circuit splits over this section — watch for a citation surge after a change or a disagreement. The dip in the last several years is a data-coverage gap, not a real trend — our corpus holds fewer opinions from the most recent years, so recent citations are undercounted.
The laws of the several states, except where the Constitution or treaties of the United States or Acts of Congress otherwise require or provide, shall be regarded as rules of decision in civil actions in the courts of the United States, in cases where they apply.
Editorial notes U.S. Code · Office of the Law Revision Counsel
Historical Revision Notes
Based on title 28, U.S.C., 1940 ed., §725 (R.S. §721).
“Civil actions” was substituted for “trials at common law” to clarify the meaning of the Rules of Decision Act in the light of the Federal Rules of Civil Procedure. Such Act has been held to apply to suits in equity.
Changes were made in phraseology.