Collateral estoppel, also known as issue preclusion, is a legal doctrine that prevents a party from relitigating an issue that a court has finally determined in a previous lawsuit. Collateral estoppel promotes judicial efficiency, prevents inconsistent judgments, and protects parties from harassment through repeated litigation on the same issue.
For collateral estoppel to apply, the following conditions generally must be met:
- Identity of Issues: The issue in the current case must be identical to the one litigated in the previous case. This means that the same legal or factual issue must have been decided in the earlier case.
- Actual Litigation: The issue must have been litigated and decided in the previous case. It is not enough if the issue was solely raised or could have been raised.
- Final Judgment: The decision on the issue in the previous case must have been a final judgment, meaning that the case has been fully and finally adjudicated, usually after appeals have been exhausted.
- Mutuality or Non-Mutuality: In traditional common law, collateral estoppel requires mutuality, meaning that the previous judgment bound both parties in the current case. However, modern trends in many jurisdictions have relaxed this requirement, allowing non-mutual collateral estoppel in certain circumstances.
Collateral estoppel can be a powerful defense in legal proceedings because it prevents parties from re-litigating issues that have already been conclusively determined. However, its application is subject to scrutiny by the courts to ensure fairness and justice. If the previous litigation’s circumstances were fundamentally unfair, collateral estoppel may not be applied.
