Under what condition can supplemental jurisdiction be exercised?

Supplemental jurisdiction allows a federal court to hear additional claims that are related to a case for which the court already has original jurisdiction. The primary condition for exercising supplemental jurisdiction is indeed that the court must have original jurisdiction over at least one claim. This means that the court has the authority to hear at least one of the claims on its docket—typically through federal question jurisdiction (cases that arise under federal law) or diversity jurisdiction (cases involving parties from different states and meeting the required amount in controversy).

Once the court establishes original jurisdiction, it can exercise supplemental jurisdiction over related claims that may not independently meet the jurisdictional requirements, provided these claims arise from a common nucleus of operative fact. This allows for efficient resolution of related issues in a single legal proceeding.

In contrast, options suggesting that supplemental jurisdiction is contingent upon both claims involving federal law, that all parties must be from the same state, or that the claims must be identical do not align with the principles of supplemental jurisdiction. These stipulations do not conform to the law as it stands, which permits additional claims as long as one original jurisdiction requirement is satisfied.