Federal Rule of Civil Procedure 24

Go To Rule 24 Essential Points

Rule 24. Intervention

(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.


(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.

Essential Points

  • As discussed, the Federal Rules generally favor getting related claims in one action and also getting related parties in one action.  Rule 24 allows parties outside the case to insert themselves into the action (intervene).  There are two types of intervention: intervention as of right and permissive intervention.
  • Rule24(a) requires courts to allow parties outside the case to intervene if given the right by statute or if the intervening party can show 1) an interest related to subject of the action; 2) that interest will be impaired by the disposition of the action; and 3) that the intervening party’s interests are not sufficiently represented by existing parties.
    • You might want to look at Sierra Club v Epsy, 18 F.3d 1502 (5th Cir. 1994) a Fifth Circuit Court of Appeals, decision discussing intervention.  In a lawsuit between the Sierra Club (an environmental group) and the government, the Court agreed that timber trade association members must be allowed to intervene because the disposition of the lawsuit would affect their economic interests and the government did not adequately represent the trade groups’ interests.
    • By the way, if you are confused about case citations, have a look at my blog.
  • Pursuant to Rule 24(b), permissive intervention, a court can allow a party to intervene if a claim or defense “shares with the main action a common question of law or fact.”  This is the same standard a court can use when deciding to consolidate a case pursuant to Rule 42.