We have no more right to decline the exercise of jurisdiction which is given, than to usurp that which is not given. The one or the other would be treason to the constitution.

Cohens v. Virginia, 19 U.S. (6 Wheaton) 264, 387 (1821); with this sentence Marshall held that the United States Supreme Court has appellate jurisdiction to hear appeals from a state court in a case between a state and its own citizens, even if the case involved interpretation of a federal statute.