Federal courts are courts of limited jurisdiction. Article III, section 2 of the United States Constitution makes this principle clear by the statement that "judicial Power shall extend to all Cases . . arising under this Constitution, the Laws of the United States, and Treaties . . . and . . . to all controversies . . . between Citizens of different States . . ."' One might argue that "judicial power" under Article III is not the same thing as jurisdiction. But the exercise of jurisdiction in situations in which a federal court does not have judicial power would not be likely to yield any conclusive results between the parties. At the heart of the idea of limited jurisdiction is the concept of "cases" and "controversies." The following analysis will explore the limits of the scope of a constitutional case and will suggest that federal courts have lost sight of their expressly limited role in adjudication by expanding the scope of the constitutional case. This phenomenon has been responsible for an unwarranted intrusion by federal courts into adjudications on questions of state law.
David Lawyer, Tightening the Reigns on Pendent and Ancillary Jurisdiction, 9 SEATTLE U. L. REV. 207 (1985).