Permissive Joinder Basics

Joining Plaintiffs Under Rule 20

Permissive Joinder Basics

Rule 20(a)(1) begins, "Persons may join in one action as plaintiffs if" its conditions are met, and that opening sentence fixes the structure of everything after it.¹ The word may grants a permission, and the word if attaches conditions to it. Plaintiffs with claims against the same defendant can sue together, but no one is forced to, and only plaintiffs who meet the conditions can use the rule at all. Lawyers call this arrangement permissive joinder: the optional joinder of parties when their claims arise jointly, severally, or from the same transaction or occurrence, and a legal or factual question common to all of them will arise.² It rests on the traditional principle that the plaintiff is master of the claim, so the plaintiffs, not the court or the defendant, decide who will be parties to the suit.³

Two conditions make the permission available, and the next sections take each in turn. The first asks whether the plaintiffs assert a right to relief, jointly, severally, or in the alternative, with respect to or arising out of the same transaction, occurrence, or series of transactions or occurrences.⁴ The second asks whether any question of law or fact common to all the plaintiffs will arise in the action.⁵ These tests are cumulative, and both must be satisfied.⁶ A shared legal question therefore cannot rescue a joinder of plaintiffs whose claims grow out of unrelated events, and a shared event still leaves the common-question test to be met.

Two people hurt in one accident show both tests at work. Volt and Edison each have a claim arising out of the same accident, and whose negligence caused it is a factual issue common to both claims. Both conditions are met, so the two may join as plaintiffs in Volt's suit.⁷

The drafters allowed this because related claims are cheaper and more reliable when tried once. One court described the rule's unmistakable purpose as promoting trial convenience by avoiding multiple lawsuits, extra expense to the parties, and loss of time to the court and the litigants.⁸ Ten passengers injured in one bus collision illustrate the gain. They can pool resources and conserve expenditures, and the public benefits because the same facts are not relitigated in a succession of actions that might reach inconsistent results.⁹ Joint suit can also cost something when the claims drift apart. Passengers from a series of separate bus accidents who sue together may be seeking an unfair advantage by presenting a picture of gross wrongdoing, or may simply confuse the factfinder.¹⁰ That tension explains why the tests get a flexible, though quite generous, reading, and why the judge keeps tools for managing a joined case, which later sections cover.

Rule 20 leaves the choice with the plaintiffs because compelled joinder would override decisions that matter to each of them. Suppose Volt and the intended defendant, Wright, are citizens of Maine, and Ellsworth is a citizen of New Hampshire. If Volt and Ellsworth had to sue together, complete diversity would be lacking and the suit could not be brought in federal court. Because the rule is permissive, Ellsworth can decline to join Volt and keep her option of suing in federal court.¹¹ Timing and forum work the same way. Worzek, who could join Yee's suit, might prefer to sue at a different time or in a different court, and in that case he simply declines and brings his own suit. Yee, for her part, decides who the defendants will be by naming them.¹²

Common-law procedure shows what that choice replaced. It tied joinder to the substantive character of the plaintiffs' interests: interests classified as joint could be litigated in one action, several interests could not, and in most cases involving joint rights joinder was compelled, so genuine permissive joinder of plaintiffs hardly existed.¹³ Law courts allowed joinder only where plaintiffs shared a common-and-undivided right, while equity took a broader approach aimed at effective remedies.¹⁴ Rule 20 reflects the modern philosophy of joinder, which asks about the relation of each party to the action rather than the label on each party's interest.¹⁵

Three different questions govern joinder of parties in federal court, and Rule 20 answers only the last. Only the real party in interest can be a party, a requirement of Rule 17(a). A person must also have capacity to sue or be sued under Rule 17(b) and (c), meaning the personal qualifications legally needed to litigate; an infant or a mental incompetent, for example, lacks capacity and must sue through a representative.¹⁶ Only when those tests are met does the question become whether a person's joinder is compelled by Rule 19 or merely permitted by Rule 20.¹⁷ Closeness to the action draws the line. A person so closely tied to the case as to be needed for a just adjudication under Rule 19(a) falls under compulsion, while a person with some lesser relation is a proper party whom the plaintiff may choose to join if Rule 20's tests are met.¹⁸

Because Rule 20 only permits joinder, a qualified person who stays out of someone else's suit loses nothing by doing so. Rizzuto, injured in the same incident as Kubek, was not a party to Kubek's suit, though he knew of it and appeared as a witness. His later separate suit is not barred by res judicata: he was not a party to the first action, and the rights of different plaintiffs to relief arising from one incident are distinct claims, not a single claim merely because they share a transaction or occurrence.¹⁹ The result follows from the structure of Rule 20. If the first judgment barred everyone who could have joined, the preclusion rules would convert the rule's may into a must and force all plaintiffs with claims from one incident to sue together. Volt and Edison use the permission by suing together, Rizzuto uses it by suing alone, and the rule sanctions both choices.