Collateral estoppel

Collateral estoppel, also known as issue preclusion, is a common law estoppel doctrine that prevents a person from relitigating an issue. One summary is that "once a court has decided an issue of fact or law necessary to its judgment, that decision . . . preclude[s] relitigation of the issue in a suit on a different cause of action involving a party to the first case." The rationale behind issue preclusion is the prevention of legal harassment and the prevention of abuse of legal resources.