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A procedural device used in a civil action whereby a defendant brings into the lawsuit a third party who is not already a party to the action but may ultimately be liable for the plaintiff's claim against the defendant.

Impleader is most commonly used where the third party, often an insurance company, has a duty to indemnify, or contribute to the payment of, the plaintiff's damages. An insurance policy usually provides that if the insured is sued, the insurance company will defend him or her in court and pay any damages owed if he or she is found liable in the action. For example, suppose a person slips and falls on a home-owner's property, suffers an injury, and sues the homeowner. If the homeowner has a home-owner's policy, he may implead his insurance company by filing a third-party complaint for approval by the court. If the court permits the complaint, the insurer is brought into the action. The homeowner is now both the defendant in the action and a third-party plaintiff. If he is found liable and ordered to pay damages, the insurance company will be expected to pay all or part of those damages.

Impleader, which was known as vouching-in at COMMON LAW, is now governed by procedural rules on both the state and federal levels. "Vouching in" has its origins in the English common-law practice of "vouching to warranty." A defendant, sued by a plaintiff for the recovery of a certain piece of property, could "vouch in" another party who may have given a WARRANTY of title when the property was sold to the defendant. Similar types of third-party actions began to appear in this country and eventually, in the interests of uniformity, a federal rule of civil procedure providing for impleader was adopted. Rule 14 of the Federal Rules of Civil Procedure provides that "a defending party, as a third-party plaintiff, may cause a summons and complaint to be served upon a person not a party to the action who is or may be liable to the third-party plaintiff for all or part of the plaintiff's claim against the third-party plaintiff."State rules of civil procedure regulate the use of impleader in actions commenced in state courts. In Connecticut, for instance,"a defendant in any civil action may move the court for permission to serve a writ, summons and complaint upon a person not a party to the action who is or may be liable to him for all or part of the plain-tiff's claim against him" (Conn. R. Super. Ct. 117). Both federal and state court impleader rules are designed to promote judicial economy by disposing of two or more trials in one action, thus eliminating the need for the defendant to sue the third party at a later time.

A third party who is brought into an action through impleader is entitled to defend herself or himself against the claims of both the plaintiff and the defendant, raising whatever defenses may be applicable. An insurance company may allege that the policy issued to the defendant does not cover the acts that gave rise to the lawsuit and thus led the defendant to implead the company. For example, suppose Ann has been sued for allegedly assaulting Susan and has filed an impleader to have her insurance company defend her and pay any damages against her. The insurance company may refuse to defend her on the ground that the policy does not cover intentional acts, such as assaulting another person. If the court agrees, the insurance company will not have to defend Susan or pay any damages that Ann is awarded by the court or a jury.

The court has a great deal of discretion in deciding whether a defendant may implead a third party. The court considers a number of factors, including whether joining the third party will unduly complicate the action, cause delay in deciding the main action (the original suit brought by the plaintiff against the defendant), adversely affect the plaintiff, or confuse the jury. If any of these factors is present, the court may refuse to permit the impleader. The court's decision to grant or deny the impleader will be over-turned by an appellate court only if it appears that the lower court abused its discretion.


Wicks, James M., and Marie Zweig. 1999. "Impleader Practice in New York: Does It Really Discourage Piecemeal Litigation?" New York State Bar Journal 71 (February): 44.

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