ANCILLARY JURISDICTION

In some cases federal courts hear claims over which no statute confers federal jurisdiction. Typically, this ancillary jurisdiction has been exercised in cases brought under the federal courts' diversity jurisdiction. Suppose a California citizen sues an Arizona citizen in federal court, claiming a right to property. If another Californian claims the same property interest, no state court can take jurisdiction over the property under the federal court's control. It is thus necessary for the federal court to be able to hear that claim, even though the case of one Californian against another would not initially be within its jurisdiction. Similarly, a defendant sued in federal court can file a third-party claim against a co-citizen, which will be heard under the federal court's ancillary jurisdiction.

Ancillary jurisdiction is sometimes confused with pendent jurisdiction, which permits a state claim to be heard in federal court along with a closely related federal question. Ancillary jurisdiction results in the addition of a party who otherwise would not fall within the federal court's jurisdiction. The Supreme Court has not been hospitable to the suggestion that a federal court in a federal question case should take "pendent" jurisdiction over a closely related state law claim against a new party.

Kenneth L. Karst
(1986)

Bibliography

Wright, Charles Alan 1983 The Law of Federal Courts, 4th ed. Pages 28–32. St. Paul, Minn.: West Publishing Co.