---
title: Res Judicata and Collateral Estoppel
description: An overview of the legal doctrines of res judicata and collateral estoppel and their application in civil litigation.
keywords: 
  - res judicata
  - collateral estoppel
  - issue preclusion
  - claim preclusion
  - civil litigation
category: law
---

## Introduction to Res Judicata and Collateral Estoppel

The legal doctrines of res judicata and collateral estoppel are fundamental principles of civil litigation that serve to promote the finality of judgments and prevent the relitigation of claims or issues that have already been fully and fairly adjudicated. Res judicata, also known as claim preclusion, bars a party from bringing a subsequent lawsuit on the same claim or cause of action that was previously litigated and resulted in a final judgment on the merits. Collateral estoppel, or issue preclusion, prevents a party from relitigating an issue of fact or law that was necessarily decided in a prior action, even if the subsequent action is based on a different claim. These doctrines are rooted in the public policy goals of judicial economy, repose for parties, and the avoidance of inconsistent judgments. 

## Elements of Res Judicata

For the doctrine of res judicata to apply, the following elements must be satisfied: (1) a final judgment on the merits in the prior action; (2) the prior action involved the same parties or their privies; and (3) the claim in the subsequent action is the same as the claim that was raised or could have been raised in the prior action. See, e.g., Parklane Hosiery Co. v. Shore, 439 U.S. 322, 326 (1979). The rationale behind res judicata is that a party who has had one full and fair opportunity to litigate a claim should not be permitted to do so again. Kremer v. Chem. Constr. Corp., 456 U.S. 461, 466 n.6 (1982).

The scope of a "claim" for res judicata purposes is construed broadly, encompassing all rights of the plaintiff to remedies against the defendant with respect to all or any part of the transaction, or series of connected transactions, out of which the action arose. Restatement (Second) of Judgments § 24 (1982). This is known as the "transactional" test, which focuses on the underlying facts giving rise to the plaintiff's claims rather than the legal theories asserted. Accordingly, a plaintiff may be barred from bringing a subsequent action even if it asserts a new legal theory or seeks different relief, as long as the claim arises from the same transaction or series of transactions. See, e.g., Federated Dep't Stores, Inc. v. Moitie, 452 U.S. 394, 398 (1981).

## Exceptions to Res Judicata

There are limited exceptions to the application of res judicata. For example, res judicata will not apply if the plaintiff was unable to obtain relief on its claim in the prior action due to a restriction on the subject matter jurisdiction of the court. See Restatement (Second) of Judgments § 26(1)(c). Additionally, res judicata may not bar a subsequent action if there has been a substantial change in the applicable legal context between the two actions. See id. § 26(1)(b). However, these exceptions are narrowly construed, and the burden is on the party seeking to avoid the preclusive effect of res judicata to demonstrate that an exception applies. See Kremer, 456 U.S. at 485.

## Elements of Collateral Estoppel

The doctrine of collateral estoppel, or issue preclusion, prevents a party from relitigating an issue of fact or law that was actually litigated and necessarily decided in a prior action, provided that the party against whom preclusion is asserted had a full and fair opportunity to litigate the issue. See Parklane Hosiery, 439 U.S. at 326 n.5. The key elements of collateral estoppel are: (1) the issue sought to be precluded is the same as that involved in the prior action; (2) the issue was actually litigated and decided in the prior action; (3) the determination of the issue in the prior action was a critical and necessary part of the judgment; and (4) the party against whom collateral estoppel is asserted had a full and fair opportunity to litigate the issue in the prior action. See, e.g., Kremer, 456 U.S. at 480-81.

Unlike res judicata, which bars the entire claim, collateral estoppel only precludes the relitigation of specific issues that were previously adjudicated. This can have significant implications for the scope of the subsequent litigation, as it may narrow the issues to be tried and the evidence that can be presented. Collateral estoppel can be applied both offensively, where a plaintiff seeks to foreclose the defendant from litigating an issue, and defensively, where a defendant seeks to prevent a plaintiff from relitigating an issue the plaintiff has previously lost. See Parklane Hosiery, 439 U.S. at 329-31.

## Exceptions to Collateral Estoppel

Like res judicata, there are limited exceptions to the application of collateral estoppel. For example, collateral estoppel may not apply if there has been an intervening change in the applicable law between the two actions. See Restatement (Second) of Judgments § 28(2)(b). Additionally, collateral estoppel may not be appropriate if the party against whom it is asserted did not have a full and fair opportunity to litigate the issue in the prior action, such as where the procedural opportunities or incentives were significantly limited. See id. § 28(5). The burden is on the party opposing the application of collateral estoppel to demonstrate that an exception applies.

## Relationship Between Res Judicata and Collateral Estoppel

While res judicata and collateral estoppel are distinct legal doctrines, they are closely related and often arise in the same context. Res judicata bars the relitigation of an entire claim or cause of action, while collateral estoppel precludes the relitigation of specific issues that were actually litigated and necessarily decided in a prior action. In many cases, the application of res judicata will also implicate collateral estoppel, as the issues that were necessarily decided in the prior action will be precluded from being relitigated in a subsequent action. However, collateral estoppel can apply even if res judicata does not, such as where the subsequent action involves a different claim or cause of action. Accordingly, the doctrines of res judicata and collateral estoppel should be considered together when evaluating the preclusive effect of a prior judgment.