A cause of action is the legal basis for a lawsuit. It is the set of facts that gives a person the right to ask a court for a remedy. Without a cause of action, a lawsuit gets dismissed. The plaintiff must identify the specific legal theory: breach of contract, negligence, defamation, trespass, and so on.

Each cause of action has elements. Negligence requires duty, breach, causation, and damages. Breach of contract requires a valid contract, performance by the plaintiff, breach by the defendant, and damages. If any element is missing, the claim fails. Lawyers plead causes of action in the complaint, and judges evaluate whether the facts support them.

Common causes of action

• Negligence: failure to exercise reasonable care.
• Breach of contract: failure to perform a contractual duty.
• Fraud: intentional misrepresentation of a material fact.
• Defamation: false statement harming reputation.
• Trespass: unauthorized entry onto property.

The statute of limitations sets a deadline for filing each cause of action. Miss it and the claim is barred, no matter how strong the facts. Different causes of action have different deadlines. Personal injury might be two years. Written contracts might be six. Figuring out the right cause of action and the right deadline is one of the first things a lawyer does when a client walks in the door.