Parallel litigation is a scenario in which different

court A court is any person or institution, often as a government institution, with the authority to adjudicate legal disputes between parties and carry out the administration of justice in civil, criminal, and administrative matters in accordance ...

s are hearing the same claim(s). In the United States, parallel litigation (and the "race to judgement" that results)is a consequence of its system of "dual sovereignty, in which both state and federal courts have personal jurisdiction over the parties. A major exception to this rule is that a second parallel In rem proceeding will be enjoined by the first court to obtain jurisdiction, as it has already been drawn into constructive possession of the object of the dispute. In rare cases the federal courts have announced a policy of not hearing (

abstaining Abstention is a term in election procedure for when a participant in a vote either does not go to vote (on election day) or, in parliamentary procedure, is present during the vote, but does not cast a ballot. Abstention must be contrasted with ...

from) a case when there is parallel litigation going on in state courts, following the Colorado River abstention doctrine. In that case, the federal government sued for adjudication of certain water rights in

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

; parties to a state court proceeding joined the U.S. as a defendant, and the Supreme Court said the federal courts should defer to that parallel litigation. This analysis can be conceptualized as a Forum non conveniens analysis in which there is already an alternative forum in play. The general rule is that " stention from the exercise of federal jurisdiction is the exception, not the rule." Moses H. Cone Mem'l Hosp. v. Mercury Constr. Corp., 460 U.S. 1, 14 (1983) (citing Colo. River Water Conserv. Distr. v. United States, 424 U.S. 800, 813 (1976)).

See also