Cause of action

A cause of action or right of action, in law, is a set of facts sufficient to justify suing to obtain money or property, or to justify the enforcement of a legal right against another party. The term also refers to the legal theory upon which a plaintiff brings suit (such as breach of contract, battery, or false imprisonment). The legal document which carries a claim is often called a 'statement of claim' in English law, or a 'complaint' in U.S. federal practice and in many U.S. states. It can be any communication notifying the party to whom it is addressed of an alleged fault which resulted in damages, often expressed in amount of money the receiving party should pay/reimburse.

To pursue a cause of action, a plaintiff pleads or alleges facts in a complaint, the pleading that initiates a lawsuit. A cause of action generally encompasses both the legal theory (the legal wrong the plaintiff claims to have suffered) and the remedy (the relief a court is asked to grant). Often the facts or circumstances that entitle a person to seek judicial relief may create multiple causes of action. Although it is fairly straightforward to file a statement of claim in most jurisdictions, if it is not done properly, then the filing party may lose their case due to simple technicalities. The need to balance procedural expediency and continuity (the technicalities of which one might fall foul) expressed as procedural rules.

There are a number of specific causes of action, including: contract-based actions; statutory causes of action; torts such as assault, battery, invasion of privacy, fraud, slander, negligence, intentional infliction of emotional distress; and suits in equity such as unjust enrichment and quantum meruit.

The points a plaintiff must prove to win a given type of case are called the "elements" of that cause of action. An element is a required part of a cause of action.^{[citation needed]}

For example, for a claim of negligence, the elements are: the (existence of a) duty, breach (of that duty), proximate cause (by that breach), and damages. If a complaint does not allege facts sufficient to support every element of a claim, the court, upon motion by the opposing party, may dismiss the complaint for failure to state a claim for which relief can be granted.

The defendant to a cause of action must file an "Answer" to the complaint in which the claims can be admitted or denied (including denial on the basis of insufficient information in the complaint to form a response). The answer may also contain counterclaims in which the "Counterclaim Plaintiff" states its own causes of action. Finally, the answer may contain affirmative defenses. Most defenses must be raised at the first possible opportunity either in the answer or by motion or are deemed waived. A few defenses, in particular a court's lack of subject matter jurisdiction, need not be pleaded and may be raised at any time.

Implied cause of action is a term used in United States statutory and constitutional law for circumstances when a court will determine that a law that creates rights also allows private parties to bring a lawsuit, even though no such remedy is explicitly provided for in the law. Implied causes of action arising under the Constitution of the United States are treated differently from those based on statutes.

Perhaps the best known case creating an implied cause of action for constitutional rights is Bivens v. Six Unknown Named Agents, 403 U.S. 388 (1971). In that case, the United States Supreme Court ruled that an individual whose Fourth Amendment freedom from unreasonable search and seizures had been violated by federal agents could sue for the violation of the Amendment itself, despite the lack of any federal statute authorizing such a suit. The existence of a remedy for the violation was implied from the importance of the right violated.