structural:scholar_edition
Title III – Pleadings and Motions

Rule 13 describes when a defendant is allowed or required to assert claims against other parties to the suit (joinder). The law encourages people to resolve all their differences as efficiently as possible; consequently, in many jurisdictions, counterclaims (claims against an opposing party) that arise out of the same transaction or occurrence (compulsory counterclaims) must be brought during the original suit, or they will be barred from future litigation (preclusion). Any counterclaims may be brought, even if they are not compulsory (permissive counterclaims), however a crossclaim (claims against a coparty), while not compulsory, must arise out of the same transaction or occurrence of the original suit or a counterclaim, or it must relate to the property in the original suit.