Rule 24 – Intervention

(through July 14, 2022)

(a) Intervention of Right. On timely motion, the court must permit anyone to intervene who: (1) is given an unconditional right to intervene by a federal statute; or (2) claims an interest relating to the property or transaction that is the subject of the action, and is so situated that disposing of the action may as a practical matter impair or impede the movant’s ability to protect its interest, unless existing parties adequately represent that interest.

(b) Permissive Intervention. (1) In General. On timely motion, the court may permit anyone to intervene who: (A) is given a conditional right to intervene by a federal statute; or (B) has a claim or defense that shares with the main action a common question of law or fact. (2) By a Government Officer or Agency. On timely motion, the court may permit a federal or state governmental officer or agency to intervene if a party’s claim or defense is based on: (A) a statute or executive order administered by the officer or agency; or (B) any regulation, order, requirement, or agreement issued or made under the statute or executive order. (3) Delay or Prejudice. In exercising its discretion, the court must consider whether the intervention will unduly delay or prejudice the adjudication of the original parties’ rights.

(c) Notice and Pleading Required. A motion to intervene must be served on the parties as provided in Rule 5. The motion must state the grounds for intervention and be accompanied by a pleading that sets out the claim or defense for which intervention is sought.

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Selected Committee Notes 

In attempting to overcome certain difficulties which have arisen in the application of present Rule 24(a)(2) and (3), this amendment draws upon the revision of the related Rules 19 (joinder of persons needed for just adjudication) and 23 (class actions), and the reasoning underlying that revision.

Rule 24(a)(3) as amended in 1948 provided for intervention of right where the applicant established that he would be adversely affected by the distribution or disposition of property involved in an action to which he had not been made a party. Significantly, some decided cases virtually disregarded the language of this provision. Thus Professor Moore states: “The concept of a fund has been applied so loosely that it is possible for a court to find a fund in almost any in personam action.” 4 Moore’s Federal Practice, par. 24.09[3], at 55 (2d ed. 1962), and see, e.g., Formulabs, Inc. v. Hartley Pen Co., 275 F.2d 52 (9th Cir. 1960). This development was quite natural, for Rule 24(a)(3) was unduly restricted. If an absentee would be substantially affected in a practical sense by the determination made in an action, he should, as a general rule, be entitled to intervene, and his right to do so should not depend on whether there is a fund to be distributed or otherwise disposed of. Intervention of right is here seen to be a kind of counterpart to Rule 19(a)(2)(i) on joinder of persons needed for a just adjudication: where, upon motion of a party in an action, an absentee should be joined so that he may protect his interest which as a practical matter may be substantially impaired by the disposition of the action, he ought to have a right to intervene in the action on his own motion. See Louisell & Hazard, Pleading and Procedure: State and Federal 749–50 (1962).

The general purpose of original Rule 24(a)(2) was to entitle an absentee, purportedly represented by a party, to intervene in the action if he could establish with fair probability that the representation was inadequate. Thus, where an action is being prosecuted or defended by a trustee, a beneficiary of the trust should have a right to intervene if he can show that the trustee’s representation of his interest probably is inadequate; similarly a member of a class should have the right to intervene in a class action if he can show the inadequacy of the representation of his interest by the representative parties before the court.

Original Rule 24(a)(2), however, made it a condition of intervention that “the applicant is or may be bound by a judgment in the action,” and this created difficulties with intervention in class actions. If the “bound” language was read literally in the sense of res judicata, it could defeat intervention in some meritorious cases. A member of a class to whom a judgment in a class action extended by its terms (see Rule 23(c)(3), as amended) might be entitled to show in a later action, when the judgment in the class action was claimed to operate as res judicata against him, that the “representative” in the class action had not in fact adequately represented him. If he could make this showing, the class-action judgment might be held not to bind him. See Hansberry v. Lee, 311 U.S. 32 (1940). If a class member sought to intervene in the class action proper, while it was still pending, on grounds of inadequacy of representation, he could be met with the argument: if the representation was in fact inadequate, he would not be “bound” by the judgment when it was subsequently asserted against him as res judicata, hence he was not entitled to intervene; if the representation was in fact adequate, there was no occasion or ground for intervention. See Sam Fox Publishing Co. v. United States, 366 U.S. 683 (1961); cf. Sutphen Estates, Inc. v. United States, 342 U.S. 19 (1951). This reasoning might be linguistically justified by original Rule 24(a)(2); but it could lead to poor results. Compare the discussion in International M. & I. Corp. v. Von Clemm, 301 F.2d 857 (2d Cir. 1962); Atlantic Refining Co. v. Standard Oil Co., 304 F.2d 387 (D.C.Cir. 1962). A class member who claims that his “representative” does not adequately represent him, and is able to establish that proposition with sufficient probability, should not be put to the risk of having a judgment entered in the action which by its terms extends to him, and be obliged to test the validity of the judgment as applied to his interest by a later collateral attack. Rather he should, as a general rule, be entitled to intervene in the action.

The amendment provides that an applicant is entitled to intervene in an action when his position is comparable to that of a person under Rule 19(a)(2)(i), as amended, unless his interest is already adequately represented in the action by existing parties. The Rule 19(a)(2)(i) criterion imports practical considerations, and the deletion of the “bound” language similarly frees the rule from undue preoccupation with strict considerations of res judicata.

The representation whose adequacy comes into question under the amended rule is not confined to formal representation like that provided by a trustee for his beneficiary or a representative party in a class action for a member of the class. A party to an action may provide practical representation to the absentee seeking intervention although no such formal relationship exists between them, and the adequacy of this practical representation will then have to be weighed. See International M. & I. Corp. v. Von Clemm, and Atlantic Refining Co. v. Standard Oil Co., both supra; Wolpe v. Poretsky, 144 F.2d 505 (D.C.Cir. 1944), cert. denied, 323 U.S. 777 (1944); cf. Ford Motor Co. v. Bisanz Bros., 249 F.2d 22 (8th Cir. 1957); and generally, Annot., 84 A.L.R.2d 1412 (1961).

An intervention of right under the amended rule may be subject to appropriate conditions or restrictions responsive among other things to the requirements of efficient conduct of the proceedings.

Key Civ Pro Laws (MBE/MEE)

Constitutional Provisions

U.S. Code


  • Rule 3 – Commencing an action
  • Rule 4 – Summons
  • Rule 6 – Computing and extending time
  • Rule 7 – Pleadings allowed
  • Rule 8 – General pleading rules
  • Rule 9 – Pleading special matters
  • Rule 10 – Form of pleadings
  • Rule 11 – Signing pleadings, motions, and other papers
  • Rule 12 – Defenses and objections
  • Rule 13 – Counterclaim and crossclaim
  • Rule 14 – Third-party practice
  • Rule 15 – Amended and supplemental pleadings
  • Rule 16 – Pretrial conferences, scheduling, management
  • Rule 19 – Required joinder of parties
  • Rule 20 – Permissive joinder of parties
  • Rule 22 – Interpleader
  • Rule 23 – Class actions
  • Rule 24 – Intervention
  • Rule 25 – Substitution
  • Rule 26 – Duty to disclose
  • Rule 30 – Depositions by oral examination
  • Rule 31 – Depositions by written questions
  • Rule 33 – Interrogatories
  • Rule 34 – Producing documents, electronically stored information, and tangible things
  • Rule 35 – Physical and mental examinations
  • Rule 36 – Requests for admission
  • Rule 37 – Failure to make disclosures or to cooperate in discovery
  • Rule 38 – Right to a jury trial
  • Rule 41 – Dismissal of actions
  • Rule 42 – Consolidation; separate trials
  • Rule 45 – Subpoena
  • Rule 47 – Selecting jurors
  • Rule 48 – Number of jurors; verdict; polling
  • Rule 49 – Special verdict; general verdict and questions
  • Rule 50 – Judgment as a matter of law in a jury trial
  • Rule 51 – Instructions to the jury; objections; preserving a claim of error
  • Rule 52 – Findings and conclusions by the court; judgment on partial findings
  • Rule 54 – Judgment, costs
  • Rule 55 – Default
  • Rule 56 – Summary judgment
  • Rule 59 – New trial; altering or amending a judgment
  • Rule 60 – Relief from a judgment or order
  • Rule 65 – Injunctions and restraining orders