Rule 13 of the Federal Rules of Civil Procedure governs counterclaims in federal court. Some counterclaims are mandatory, meaning that the party being sued must sue the party suing him. Counterclaims are mandatory as a general rule if the claims arise out of the same transaction or occurrence as the claim of the opposing party. For example, if A sues B for breaching a contract, B must sue A for breaching the contract in the same action. If B does not sue A in the same action for breaching the contract, then B will probably never be able to sue A for breaching the contract because B failed to assert a mandatory counterclaim.
Rule 13(a)(2)(B) Creates an Unusual Exception
There are a few exceptions to Rule 13’s requirements that a party being sued must assert a counterclaim if the counterclaim arises out of the same transaction or occurrence as the claim raised by the opposing party. One exception is found in Rule 13(a)(2)(B). This exception is very unusual and rarely comes up in court. But it could be a tricky question on a civ pro law school examination.
Rule 13(a)(2)(B) addresses circumstances where a plaintiff attaches property – – in an attachment a court grants the plaintiff rights to the property – – and a defendant enters the case to defend against plaintiff’s right to the property. The plaintiff never asked the Court to assert personal jurisdiction over the defendant. However, the defendant chooses to enter the case to defend against the claim. Rule 13 says that under these circumstances the defendant does not have to assert any counterclaims. The idea is that it would be unfair to the defendant to require him to assert his counterclaims if he only chose to enter the case to protect rights to the property. The Court was not asked at the outset of the case to assert personal jurisdiction over him.
But remember, if the defendant chooses to assert any counterclaim, then he must assert all mandatory counterclaims. Once he asserts a counterclaim, he loses the protection of Rule 13 (a)(2)(B) and will also have to raise his counterclaims. Otherwise, Rule 13 gives the defendant a pass to enter the case without asserting a mandatory counterclaim.