Anti-Injunction Act

Federal courts may not enjoin state proceedings except as authorized by statute, necessary to aid jurisdiction, or to protect judgments.

Related Federal Court Doctrines rules

• Mootness DoctrineA case is moot when no live controversy remains, unless an exception applies.
• Ripeness DoctrineA claim is unripe when it is premature for judicial review.
• Standing: Injury in FactStanding requires a concrete and particularized injury that is actual or imminent.
• Standing: Causation & RedressabilityCausation requires the injury be fairly traceable to defendant; redressability requires a likely remedy.
• Third-Party StandingThird-party standing requires close relationship and hindrance to the third party asserting their own rights.
• Associational StandingAssociations may sue on behalf of members when members have standing and participation is unnecessary.
• Advisory OpinionsFederal courts may not issue advisory opinions absent an actual case or controversy.
• Political Question DoctrinePolitical questions are nonjusticiable when textually committed to another branch or lacking judicially manageable…

Part of Civil Procedure on Core Legal Rules — foundational MBE-tested principles with primary-source citations.