MBE Rules · Civil Procedure
Counterclaims — compulsory vs permissive
FRCP 13
The rule
Compulsory (13(a)): arises out of the same transaction or occurrence as the opposing claim — MUST be pled or waived. Permissive (13(b)): any other claim — MAY be pled. Compulsory counterclaims have automatic supplemental jurisdiction.
In plain English
If your claim is directly related to the other party's claim, you have to bring it up in the same lawsuit. If it's unrelated, you can choose whether to bring it up or not.
Worked example
The defendant is sued for a car accident. If they want to claim the plaintiff owes them money from a previous loan, they don't have to do it in this case. But if it's about the accident damages, they must include it.
Memory hook
Compulsory = Connected, Permissive = Pick. If it's related, you must state it, or lose it.
The trap
Students think: Any counterclaim can be saved for later. Wrong, because compulsory ones must be filed or they're waived. The actual test is whether it arises from the same transaction or occurrence.
How examiners test it
The MBE loves: two parties with multiple disputes. Question: Is this counterclaim compulsory? Trap: Students miss 'same transaction or occurrence' link, focusing on unrelated facts instead.
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