Cross-Claim

A cross-claim is a pleading device that allows a litigant to assert a claim against another party aligned on the same side of an existing lawsuit — most commonly co-defendant against co-defendant, or co-plaintiff against co-plaintiff. It is distinct from a counterclaim, which runs against an opposing party, and from a third-party claim (impleader), which brings in a new party not yet in the suit.

In United States federal practice, cross-claims are governed by Rule 13(g) of the Federal Rules of Civil Procedure. The rule permits a cross-claim only when it arises out of the same transaction or occurrence as the original action or a counterclaim, or when it relates to property that is the subject matter of the original action. Cross-claims may also include a contention that the co-party is or may be liable to the cross-claimant for all or part of a claim asserted against the cross-claimant — the typical vehicle for indemnity and contribution claims among co-defendants.

Key features:

• Permissive, not compulsory. Unlike compulsory counterclaims under Rule 13(a), a party is generally not required to bring a cross-claim, and failure to do so does not bar later litigation.
• Same-transaction requirement. Unrelated disputes between co-parties cannot be tacked onto the case.
• Supplemental jurisdiction. In federal court, cross-claims that meet Rule 13(g) typically fall within supplemental jurisdiction under 28 U.S.C. § 1367, since they share a common nucleus of operative fact with the main claim.
• Responsive pleading. The cross-defendant must answer the cross-claim much as a defendant answers a complaint.

Many U.S. state procedural codes mirror Rule 13(g), though terminology and scope vary. In international and comparative contexts, civil-law jurisdictions handle analogous disputes through joinder mechanisms or separate proceedings rather than a discrete "cross-claim" device. The concept rarely appears in public international law, where party structures before bodies like the ICJ differ substantially from domestic civil litigation.