District courts have discretion to hear pendent state claims where there is a substantial federal claim arising out of a common nucleus of operative fact. 28 U.S.C. S 1367(a); United Mine Workers v. Gibbs, 383 U.S. 715 (1966). This is a "doctrine of flexibility, designed to allow courts to deal with cases involving pendent claims in the manner that most sensibly accommodates a range of concerns and values." Carnegie-Mellon Univ. v. Cohill, 484 U.S. 343, 350 (1988).
The court must weigh "considerations of judicial economy, convenience and fairness to the litigants; if these are not present a federal court should hesitate to exercise jurisdiction over state claims." Gibbs, 383 U.S. at 726. However, "[n]eedless decisions of state law should be avoided both as a matter of comity and to promote justice between the parties, by procuring for them a surer-footed reading of applicable law." Id. If "state issues substantially predominate, . . . the state claims may be dismissed without prejudice and left for resolution to state tribunals." Id., 383 at 726-27.