Erie R. Co. v. Tompkins

In his dissent, Justice Butler, joined by Justice McReynolds, argued that the majority has held unconstitutional the Judiciary Act of 1789, "and especially section 34." He also argued that federal courts now have to adhere to state court decisions, and that Congress is now powerless to remedy the situation. "It is," he said, "hard to foresee the consequences of the radical change so made."

He also argued that it was not necessary for the Court to consider "any" constitutional question in this case, but since, as he understood the majority opinion, it had invalidated the Judiciary Act of 1789, then the Court was required by law to allow the U.S. attorney general to present arguments on behalf of the act's constitutionality. For that matter, he added, Congress would have to be consulted as well.

Butler agreed that the lower court's judgment should be reversed, not for the constitutional reasons given by the majority but because Tompkins's own negligence contributed to his injuries.

Justice Reed concurred with the majority opinion but would have preferred the Court to say "the course pursued" by federal courts based on the doctrine of Swift v. Tyson was "merely erroneous," rather than "unconstitutional."