compulsory joinder

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Compulsory joinder, also known as mandatory joinder, refers to the process of joining parties or claims, without which the suit could not proceed, to a single suit. Compulsory joinder is an aspect of both civil and criminal procedures. Failure or inability to join a compulsory party may result in dismissal of the lawsuit. 

In civil procedureRule 19 of the Federal Rules of Civil Procedure governs the compulsory joinder of parties. This rule is intended to protect a party's right to be heard and to participate in the adjudication of a claimed interest. 

Rule 19 states that a person who is subject to service of process and whose joinder will not deprive the court of subject-matter jurisdiction must be joined as a party if:

  • In that person's absence, the court cannot accord complete relief among existing parties; or
  • That person claims an interest relating to the subject of the action, and is so situated that disposing of the action in the person's absence may:
    • As a practical matter, impair or impede the person's ability to protect the interest; or
    • Leave an existing party subject to a substantial risk of incurring double, multiple, or otherwise inconsistent obligations because of the interest.

Rule 19 was amended in 2007. Prior to the amendments, the rule used the language of "necessary" and "indispensable" in referring to parties that must be joined. Traditionally, in determining whether joinder is compulsory, a court applies the following two-step test:

  • First, a court determines whether an absent party is necessary, that is, whether complete relief can be afforded to the existing parties in the litigation without the absent party.
    • In addition, a court also determines whether the absent party's interest will be impaired.
  • Next, if the absent party is necessary, but joinder is not feasible (e.g.: because of lack of jurisdiction over the party), then the court must determine whether the absent party is indispensable.
    • A party is indispensable if the litigation cannot proceed without their presence.
    • In making a determination, courts weigh the equities by considering the factors listed in Rule 19(b).

In criminal procedure, the compulsory joinder rule requires a prosecutor, in a single action, to bring all known charges against a defendant arising from a single criminal episode. This rule is meant to protect defendants from government harassment and being subjected to successive trials for offenses stemming from the same criminal episode. Additionally, the rule promotes judicial economy by avoiding repetitive litigation.

In determining whether events are part of a single criminal episode, jurisdictions apply various tests.

In California, courts apply the "Time and Place Test," as well as the "Evidentiary Test."

  • Under the Time and Place Test, charges against a defendant must be joined if they stem from the same time and location.
  • Under the Evidentiary Test, if the evidence needed to prove one offense supplies substantial proof for another offense, then the offenses must be joined.

In New York, two acts are part of the same criminal episode if they are closely related in time or criminal purpose.

[Last updated in August of 2022 by the Wex Definitions Team]