A legal rule that precludes a party from re-litigating issues and questions of fact (other than on appeal), already addressed in a previous legal proceeding (usually) between the same parties. The application of issue preclusion is highly complex and decisions in one court do not necessarily preclude addressing the issue in another court, in the same or a different way. Nonetheless, in the event that there has been litigation between the same or related parties in the past, relating to the same subject matter, the question of issue preclusion should be considered and addressed.
Usually foreign court judgments are not “issue preclusive” but they may be considered as influential on the same facts under principles of comity. In addition, various conventions, for example the Brussels Convention, may give decisions more far reaching issue preclusive effects between EU courts, while other conventions may preclude re-litigation of issues such as child custody.
Issue preclusion is sometimes inaccurately referred to as collateral estoppel; the difference is that issue preclusion is usually mandatory while collateral estoppel is at the discretion of the court. The term issue estoppel is also similarly used, although again the word estoppel indicates a mandatory loss of the right to re-litigate an issue. See Lis Pendens Rule, Standard of Review, Appellate