What governs the statute of limitations concerning supplemental jurisdiction?

The statute of limitations concerning supplemental jurisdiction is governed by state law. This is due to the fact that when a federal court exercises supplemental jurisdiction over a state law claim, it must adopt the applicable statute of limitations that governs similar state law claims in that jurisdiction.

Federal law does not provide a specific statute of limitations for state law claims because the federal courts are borrowing from state law in this context. Therefore, the relevant statute of limitations will vary based on the state in which the federal court is located and the specific type of claim being brought.

Local law and international treaties are not relevant in this context; while local rules may inform procedural aspects of cases within federal courts, they do not supersede the necessary application of state law regarding limitations. International treaties do not pertain to domestic civil procedure in the context of supplemental jurisdiction either. Thus, state law provides the framework for determining how long a litigant has to file a claim, if that claim is brought under supplemental jurisdiction in a federal court.