Cause of Action

A cause of action is the legal and factual basis on which a claimant brings a lawsuit. It bundles together two things: (1) the underlying facts alleged by the plaintiff, and (2) the legal theory (statute, treaty provision, common-law doctrine, or constitutional clause) that entitles the plaintiff to a remedy if those facts are proven.

Every cause of action has identifiable elements that the plaintiff must plead and ultimately prove. For a negligence claim in most common-law jurisdictions, the elements are duty, breach, causation, and damages. For a breach-of-contract claim, the plaintiff typically must show a valid contract, performance (or excuse), breach, and resulting loss. Failure to plead any element allows the defendant to move for dismissal — in U.S. federal practice, under Rule 12(b)(6) for "failure to state a claim upon which relief can be granted."

In international and public law contexts relevant to IR researchers, the term takes on a related but distinct meaning. Before a state or individual can bring a claim before a tribunal such as the International Court of Justice or the European Court of Human Rights, there must be a recognized cause of action grounded in a treaty, customary international law, or a jurisdictional clause. For example, claims under the Convention on the Prevention and Punishment of the Crime of Genocide must invoke Article IX as the jurisdictional and substantive basis.

Key features to remember:

• Distinct from "right of action" — the latter refers to who may sue; the cause of action defines what may be sued upon.
• Claim preclusion (res judicata) typically bars relitigating the same cause of action between the same parties.
• Statutes of limitations generally run from the date the cause of action accrues, i.e., when the injury and the defendant's identity are known or knowable.
• A single set of facts may give rise to multiple causes of action (e.g., the same conduct producing both tort and contract claims).