Atlantic Coast Line R.R. v. Brotherhood of Locomotive Engineers
United States Supreme Court
398 U.S. 281 (1970)
Members of the Brotherhood of Locomotive Engineers (BLE) (defendant) picketed a railroad switching yard owned by Atlantic Coast Line Railroad Company (ACL) (plaintiff) in a labor dispute. After being denied a federal injunction, ACL obtained one in state court. The Supreme Court later held in a separate case that unions had a right to such picketing under the Railway Labor Act, free from state-court injunction. When the state court refused to dissolve ACL's injunction based on that ruling, BLE went to federal court seeking to enjoin enforcement of the state injunction; the district court granted the injunction, and the court of appeals affirmed. The Supreme Court granted certiorari.
Whether federal courts are prohibited from enjoining state-court proceedings unless expressly authorized by Congress, or necessary to aid the federal court's jurisdiction or to protect or effectuate its judgments.