What is a scenario where a court must decline jurisdiction?

In this scenario, a court must decline jurisdiction when the state claim predominates over the original claim. This situation arises under the doctrine of supplemental jurisdiction, particularly when a federal court has original jurisdiction based on a federal question or diversity of citizenship. If a state claim is substantially more significant than the federal claim and has the potential to overwhelm the federal issues, the court may determine that it is more appropriate for the state court to handle the state law matters.

The focus here is on the relationship between the claims and their relative importance in the case. A court will often decline jurisdiction to avoid stepping into areas that are more appropriately governed by state law, especially when the federal issues are secondary or minor. This helps ensure that state matters are resolved in a forum that is most familiar with the law and factual context, promoting judicial efficiency and comity between federal and state systems.