FEDERAL RULES OF CIVIL PROCEDURE
Rule 17 Parties Plaintiff and Defendant; Capacity
(a) Real Party in Interest. Every action shall be prosecuted in the name of the real party in interest. An executor, administrator, guardian, bailee, trustee of an express trust, a party with whom or in whose name a contract has been made for the benefit of another, or a party authorized by statute may sue in that person's own name without joining the party for whose benefit the action is brought; and when a statute of the United States so provides, an action for the use or benefit of another shall be brought in the name of the United States. No action shall be dismissed on the ground that it is not prosecuted in the name of the real party in interest until a reasonable time has been allowed after objection for ratification of commencement of the action by, or joinder or substitution of, the real party in interest; and such ratification, joinder, or substitution shall have the same effect as if the action had been commenced in the name of the real party in interest.
(b) Capacity to Sue or be Sued. The capacity of an individual, other than one acting in a representative capacity, to sue or be sued shall be determined by the law of the individual's domicile. The capacity of a corporation to sue or be sued shall be determined by the law under which it was organized. In all other cases capacity to sue or be sued shall be determined by the law of the state in which the district court is held, except
(1) that a partnership or other unincorporated association, which has no such capacity by the law of such state, may sue or be sued in its common name for the purpose of enforcing for or against it a substantive right existing under the Constitution or laws of the United States, and
(2) that the capacity of a receiver appointed by a court of the United States to sue or be sued in a court of the United States is governed by Title 28, U.S.C. §§ 754 and 959(a).
(c) Infants or Incompetent Persons. Whenever an infant or incompetent person has a representative, such as a general guardian, committee, conservator, or other like fiduciary, the representative may sue or defend on behalf of the infant or incompetent person. An infant or incompetent person who does not have a duly appointed representative may sue by next friend or by a guardian ad litem. The court shall appoint a guardian ad litem for an infant or incompetent person not otherwise represented in an action or shall make such other order as it deems proper for the protection of the infant or incompetent person.
[As amended Dec. 27, 1946, eff. Mar. 19, 1948; Dec. 29, 1948, eff. Oct. 20, 1949; Feb. 28, 1966, eff. July 1, 1966; Mar. 2, 1987, eff. Aug. 1, 1987; Apr. 25, 1988, eff. Aug. 1, 1988; Nov. 18, 1988.]