I’m posting an un- or underexplored question about Erie Railroad Co. v. Tompkins every day this month.
Today's question: Assume that the correct reading of Brandeis’s opinion in Erie is that the Pennsylvania Supreme Court’s decisions concerning Pennsylvania common law are binding on a federal court to the extent that the Pennsylvania Supreme Court wants them to be binding. How do we know what the Pennsylvania Supreme Court's views on the matter are? Unless the question is certified, when would the issue ever come up before the Pennsylvania Supreme Court (or any other Pennsylvania state court)? My answer? Never.
Does this explain why the disagreement between advocates of Swift and Erie was so intractable? It was about state law (namely whether a state supreme court’s decisions were intended to bind federal courts) but the state supreme court never had occasion to resolve it?
(Note: This is parallel posted on Prawfsblawg.)