Baltimore & Ohio Railroad v. Kepner

We have for decision in this case the question whether a state court may validly exercise its equitable jurisdiction to enjoin a resident of the state from prosecuting a cause of action arising under the Federal Employers’ Liability Act in a federal court of another state where that Act gave venue, on the ground that the prosecution in the federal court is inequitable, vexatious and harassing to the carrier.

As the issue was deemed a federal question of substance,1 undecided by this Court, and concerning which there was lack of uniformity in the state court decisions,2 certiorari was granted,…