Anti-Injunction Act

United States federal civil procedure doctrines
Justiciability
Advisory opinions Standing Ripeness Mootness Political questions Constitutional avoidance
Jurisdiction
Subject-matter Federal question Diversity Amount in controversy Supplemental Removal Class Action Fairness Act of 2005 Personal In personam In rem Quasi in rem
Federalism
Erie doctrine Abstention Anti-Injunction Act Sovereign immunity Abrogation Rooker–Feldman doctrine Adequate and independent state ground
v t e

The Anti-Injunction Act (28 U.S.C. § 2283), is a United States federal statute that restricts a federal court's authority to issue an injunction against ongoing state court proceedings, subject to three enumerated exceptions. It states:

"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."^[1]

The Act was originally enacted as part of the Judiciary Act of 1793. The current Act was enacted in 1948. As interpreted by the Supreme Court of the United States, the Act is a bastion of federalism and embodies the need to avoid "needless friction" between state and federal courts.^[2]