Res judicata is the generic term for a group of related concepts concerning the conclusive effects given final judgments. Within this general doctrine there are two principal categories: (1) claim preclusion—also known as res judicata; and (2) issue preclusion—also known as collateral estoppel.
These legal doctrines generally preclude litigants from relitigating claims and issues that were previously litigated to a final resolution or judgment.
In Nebraska, res judicata, or claim preclusion, prevents a party from relitigating a claim that has already been finally adjudicated in a court of competent jurisdiction. Once a final judgment has been rendered, the same parties cannot bring a lawsuit on the same claim or cause of action again. This doctrine ensures finality and efficiency in the legal process by avoiding multiple lawsuits for the same matter. Issue preclusion, or collateral estoppel, is a related concept that bars the relitigation of specific issues that were already decided in a previous lawsuit between the same parties. For issue preclusion to apply, the issue must have been actually litigated, determined by a valid and final judgment, and essential to the judgment. These principles are codified in Nebraska's statutes and case law, and they are fundamental to the state's judicial system to prevent redundant litigation and to maintain the integrity of judicial decisions.