---
title: "Claim Preclusion (Res Judicata)"
type: Legal Rule
source: https://casebriefly.com/legal-rules/claim-preclusion-res-judicata
---

# Claim Preclusion (Res Judicata)

Claim preclusion bars a party from relitigating any claim that was or could have been raised in a prior action between the same parties that ended in a valid final judgment on the merits.

## Definition

Claim preclusion, also known as res judicata, is a doctrine that prevents parties from relitigating claims that were or could have been raised in a prior lawsuit. The doctrine serves the dual purposes of protecting defendants from the burden of relitigating matters already resolved and promoting judicial economy by preventing duplicative litigation. Once a valid, final judgment on the merits has been entered, it extinguishes the entire claim, including all theories of relief and all grounds for recovery that the party raised or could have raised.

Claim preclusion requires three elements: (1) a final judgment on the merits in a prior action, (2) the same parties or their privies in both actions, and (3) the same claim or cause of action in both suits. The most contested element is typically whether the same claim is involved. Courts use varying tests to define the scope of a claim, with the transactional test from the Restatement (Second) of Judgments being the most widely adopted. Under the transactional test, a claim encompasses 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.

A judgment on the merits includes not only a verdict after trial but also summary judgment, default judgment, and involuntary dismissal (though voluntary dismissal without prejudice typically does not have preclusive effect). Importantly, claim preclusion bars not only claims actually litigated but also claims that could have been raised but were not, encouraging parties to bring all related claims in a single action.

## Elements

- A valid, final judgment on the merits in the prior action
- The same parties or their privies in both actions
- The same claim or cause of action, typically defined by the transactional test
- The claim was actually raised or could have been raised in the prior action
- The prior judgment extinguishes all theories of recovery arising from the same transaction

## Key Case

Cromwell v. County of Sac, 94 U.S. 351 (1877)

## Landmark Cases

| Name | Citation | Significance |
| --- | --- | --- |
| Cromwell v. County of Sac | 94 U.S. 351 (1877) | Distinguished claim preclusion from issue preclusion: claim preclusion bars relitigation of the entire claim, while issue preclusion bars relitigation of specific issues actually decided. |
| Federated Department Stores, Inc. v. Moitie | 452 U.S. 394 (1981) | Held that claim preclusion applies even when the prior judgment was clearly erroneous; the proper remedy is appeal, not a second lawsuit. |
| Migra v. Warren City School District Board of Education | 465 U.S. 75 (1984) | Held that federal courts must give state court judgments the same preclusive effect they would have under the law of the rendering state, including claim preclusion. |
| Taylor v. Sturgell | 553 U.S. 880 (2008) | Rejected virtual representation as a basis for claim preclusion, holding that nonparties generally cannot be bound by judgments against others unless specific recognized exceptions apply. |

## Exam Tips

- Apply the transactional test to determine the scope of the claim: would the facts giving rise to the second suit have been part of the same transaction or occurrence as the first?
- Remember that claim preclusion bars claims that could have been brought but were not. This use it or lose it aspect is frequently tested.
- Check whether the judgment in the prior action was truly on the merits. Dismissals for lack of jurisdiction are not on the merits and do not trigger claim preclusion.
- Distinguish claim preclusion from issue preclusion: claim preclusion bars entire claims; issue preclusion bars specific issues actually litigated and decided.

## Common Mistakes

- Applying claim preclusion when the prior dismissal was for lack of jurisdiction or improper venue, which are not judgments on the merits.
- Confusing claim preclusion with issue preclusion: claim preclusion bars an entire cause of action, while issue preclusion bars relitigation of specific factual or legal issues.
- Forgetting the privity requirement and attempting to apply claim preclusion against or by nonparties who are not in privity with the original parties.

## Mnemonic Or Memory Aid

Claim preclusion = same claim, same parties, final judgment. Use it or lose it: bring all related claims or they are barred.

## Related Rules

- issue-preclusion-collateral-estoppel
- joinder-of-claims-rule-18
- class-action-requirements-rule-23

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Source: [Claim Preclusion (Res Judicata) — CaseBriefly](https://casebriefly.com/legal-rules/claim-preclusion-res-judicata)