Colorado River abstention; parallel litigation

The Colorado River abstention, from Colorado River Water Conservation District v. United States, 424 U.S. 800 (1976) comes into play where parallel litigation is being carried out, particularly where federal and state court proceedings are simultaneously being carried out to determine the rights of parties with respect to the same questions of law. Under such circumstances, it makes little sense for two courts to expend the time and effort to achieve a resolution of the question.

Unlike other abstention doctrines, application of the Colorado River doctrine is prudential and discretionary, and is based less on comity or respect between different court systems than on the desire to avoid wasteful duplication of litigation. The classification of the doctrine as a form of abstention has been disputed, with some courts simply calling it a "doctrine of exceptional circumstances". Each of the various federal circuits has come up with its own list of factors to weigh in determining whether a federal court should abstain from hearing a case under this doctrine. Typically, such factors include:
  1. the order in which the courts assumed jurisdiction over property
  2. the order in which the courts assumed jurisdiction over the parties
  3. the relative inconvenience of the fora
  4. the relative progress of the two actions (added by Moses H. Cone Memorial Hospital v. Mercury Constr. Corp. in 1983)
  5. the desire to avoid piecemeal litigation
  6. whether federal law provides the rule of decision
  7. whether the state court will adequately protect the rights of all parties
  8. whether the federal filing was vexatious (intended to harass the other party) or reactive (in response to adverse rulings in the state court).