What is the general purpose and basic requirement of res judicata (claim preclusion)?

• A. To prevent relitigation of issues actually litigated and essential to a prior judgment.
• B. To prevent a later claim arising from the same transaction after final judgment.
• C. To preclude a later claim arising from the same transaction or occurrence after a final judgment on the merits.
• D. It allows appeal as of right in civil cases.

Answer: (C)

Res judicata, or claim preclusion, is about finality and efficiency in litigation. Once there is a final judgment on the merits in a prior case, a later claim arising from the same transaction or occurrence by the same parties (or their privies) is barred. The requirement of a final judgment on the merits ensures the prior decision actually resolved the substantive rights and obligations, not just some procedural issue. The “same transaction or occurrence” part ties the second claim to the same core facts and dispute, so you can’t relitigate the same core controversy after it’s been decided.

The other options fit different concepts or are incomplete. The first describes relitigating issues actually litigated and essential to a judgment, which is issue preclusion rather than claim preclusion. The second misses the necessity of a final judgment on the merits. The last option about appeals doesn’t govern res judicata at all.