Anti-Injunction Act (28 U.S.C. § 2283)
“A court of the United States may not grant an injunction to stay proceedings in a State court except as expressly authorized by Act of Congress, or where necessary in aid of its jurisdiction, or to protect or effectuate its judgments.”
Three Exceptions
- Expressly authorized by Act of Congress — e.g., 28 U.S.C. § 2361 (interpleader), 28 U.S.C. § 1446 (removal), the Bankruptcy Act
- Necessary in aid of jurisdiction — typically when a federal court must protect its in rem jurisdiction over specific property; Atlantic Coast Line RR v. Brotherhood of Locomotive Engineers (1970): construed narrowly; court must have actual jurisdiction already
- Protect or effectuate judgments (relitigation exception) — prevents parties from relitigating issues already decided by a federal court (Chick Kam Choo v. Exxon Corp.); only applies to issues that were actually decided, not claims that could have been raised
Strict Construction
Leiter Minerals v. United States (1957): the three exceptions are narrow and cannot be expanded by inference. When in doubt, no injunction. Any doubts should be resolved against issuing the injunction.
Relationship to Other Doctrines
- Younger abstention: even without the AIA, federal courts generally abstain from enjoining pending criminal proceedings and certain civil proceedings in state court (Younger v. Harris)
- All Writs Act (28 U.S.C. § 1651): cannot be invoked to circumvent the AIA