The Rule 18(a) Standard

Joining Multiple Claims

Rule 18(a) answers the claim-joinder question in one sentence: “A party asserting a claim, counterclaim, crossclaim, or third-party claim may join, as independent or alternative claims, as many claims as it has against an opposing party.”¹ Joinder means combining claims or parties in a single action, and this rule covers the claims half. It tells a litigant who already has an opponent in court how much of the dispute between them the court may hear together.

The question arises the moment a plaintiff picks a forum. She must then settle the scope of the suit: whom to sue, whether to sue alone or with other plaintiffs, and which claims to assert.² Rule 18(a) governs the third decision.

A rulemaker could answer Yee's question in several ways. The most restrictive approach would confine her to a single claim, which would force three lawsuits against one man. The Federal Rules take the most liberal of the four approaches: Rule 18(a) allows a plaintiff to assert any claims she has against an opponent, whether related or unrelated.³

The text of the rule raises three questions, and each heading below takes one. Who may use the rule? Must the joined claims be related to one another? And what form may they take: independent claims, alternative claims, or both?

Who May Join Claims

Rule 18(a) identifies its users by what they are doing in the lawsuit: “[a] party asserting a claim, counterclaim, crossclaim, or third-party claim.”⁴ A plaintiff filing a complaint qualifies. So does a defendant who counterclaims, a coparty who crossclaims, and a defendant who impleads. The wording has changed over time. The 1938 text spoke in the plaintiff's voice (“the plaintiff . . . may join . . . as many claims . . . as he may have against an opposing party”); a 1987 amendment replaced “he” with “the party,” and the 2007 restyling produced the current sentence.⁵

Each named claim is a different route by which one party becomes another's adversary. A counterclaim is a claim by a defending party against an opposing party, and a crossclaim is a claim by one coparty against another that adds no new party to the case.⁶ A third-party claim comes from impleader under Rule 14(a): a defendant brings in a new party and claims a right to recover from that party what the defendant is ordered to pay the plaintiff.⁷

The rules that authorize those claims put the adversary into the case. Rule 18(a) is the more general provision that lets the same party add further claims against that adversary.⁸ A party that has properly made another party an adversary under some other joinder rule may therefore add even unrelated claims.⁹ Plaintiffs invoke claim-joinder rules most often, but the rules equally control a defendant asserting several counterclaims or crossclaims.¹⁰

Rule 13 and Rule 18(a) do different jobs here. Rule 13 sorts counterclaims: one arising out of the same transaction or occurrence as the plaintiff's claim is compulsory, and the defendant waives it by not asserting it, while an unrelated counterclaim is permissive.¹¹ Both of Brandt's counterclaims are permissive, since neither arises from the assault. Rule 13 tells Brandt which counterclaims he must bring, and Rule 18(a) lets him stack the rest against Lindqvist in one pleading.

Rule 14(a) limits the impleader claim itself. It does not allow the defendant to seek damages the defendant suffered from the underlying litigation events, for example.¹² Those limits govern how Cobalt enters the case. Once Cobalt is properly Brightline's adversary, Brightline may add unrelated claims against it under Rule 18(a).

The words “an opposing party” set the outer limit. Rule 18(a) adds claims between litigants who are already adversaries, and it cannot turn a stranger into a litigant. The party-joinder rules screen who may enter a case. Rule 20(a)(2), for example, allows defendants to be sued together only if the claims against them arise out of the same transaction or occurrence (or series of them) and involve a common question of law or fact.¹³

Students often read “as many claims as it has” as reaching anyone against whom a claimant has a grievance. The rule's closing words block that reading: the claims must be “against an opposing party,” so the target of every added claim must already be in the case as an adversary.¹⁴ Rule 18(a) says which claims may be combined between existing adversaries, and Rule 20 says who may be in the case at all. A later section takes up party joinder in full.

Rule 18(a) sets two conditions and no others: the party must actually hold the claim, and the claim must run against an opposing party. The text never asks whether the claims arise from the same transaction, the same occurrence, or the same subject matter.¹⁶ A plaintiff who sues for intentional assault and battery may add a claim that the defendant owes money on a contract that has nothing to do with the tort.¹⁷

Yee's suit against Pemberton stretches the same way. She may assert her claims for personal injury and property damage together and add her contract claim for the poor paint job. If Pemberton also painted her summer cottage, she may add a claim over that work, though it arose from completely unrelated events. She could even add an admiralty claim, one arising under maritime law, if they collided while racing yachts the previous season.¹⁸

The rule is just as indifferent to the kind of claim. It permits legal claims to be joined with equitable claims, claims resting on different legal theories, and even inconsistent claims.¹⁹ Older practice looked very different. At common law, with certain limited exceptions, only claims under the same form of action could be joined, and because law and equity were separate systems, neither court could hear a legal claim joined with an equitable one.²⁰ Procedural reform and the merger of law and equity then extended equity's joinder procedures, especially those that let complex cases be resolved in a single action.²¹ The next section traces that path.

Free joinder of claims is easier to justify than free joinder of parties. Joining a new party raises many problems, and most of them do not arise when the court is only adding a claim between parties already properly before it.²²

The rule's breadth operates at the pleading stage, and the real limits lie outside it. Federal jurisdictional requirements must still be met for a joined claim, although they are rarely restrictive.²³ The court also keeps control of the case after the pleadings close. Rule 42(b) permits it, “[f]or convenience, to avoid prejudice, or to expedite and economize,” to order a separate trial of one or more claims, and Rule 21 permits severance, which cuts individual claims off to stand as separate cases.²⁴ A jury therefore need not hear an assault claim and an unrelated contract debt together merely because one complaint contains both. Read with Rule 42(b), claim joinder is no longer rigidly restricted at the pleading stage; it becomes a matter of the court's discretion in shaping the trial.²⁵

A nonfederal claim joined to a federal one needs diversity unless the two are closely enough related on their facts to support supplemental jurisdiction.²⁶ A joined claim must also satisfy subject-matter jurisdiction independently.²⁷ Okafor's loan claim has no factual tie to the federal claim, and with both parties citizens of Ohio there is no diversity, so nothing supplies jurisdiction. Had they been citizens of different states, the same claim would raise no difficulty: diversity that supports one claim between a single plaintiff and a single defendant exists for every other claim between them, and the claims may be added together to reach the amount in controversy.²⁸ The joinder rule is identical in both pairings, and jurisdiction alone separates them.

Federal Rule 18 governs whether claims may be joined, regardless of what state law may provide.²⁹ Whether a federal rule may be applied in a case governed by state law is a separate question under the Rules Enabling Act, and a close case can be hard to resolve, as Shady Grove Orthopedic Associates, P.A. v. Allstate Insurance Co. illustrates. There a health care provider brought a class action in federal court against Allstate, claiming that it delayed paying claims and failed to pay statutory interest due on late payments under New York law.³⁰

Relatedness matters elsewhere in the joinder rules, which is why students read it into Rule 18(a). A compulsory counterclaim must, among other conditions, arise out of the same transaction or occurrence as the opposing claim, and every crossclaim must arise out of the same transaction or occurrence as the original claim.³¹ Rule 20(a)(2) likewise lets defendants be sued together only when the claims against them arise from the same transaction or occurrence and share a common question.³² In those rules relatedness works as a gate, either forcing a claim into the case or admitting a new person. Rule 18(a) operates after the gate, among parties already inside.

Independent and Alternative Claims

Rule 18(a) says a party may join its claims “as independent or alternative claims,” and the two adjectives name different relationships among them.³⁴ Independent claims are separate claims that can all succeed. Yee's claim for her injuries and her claim for the streaked paint job are independent. Alternative claims are different versions or theories of one grievance, so winning on one may mean losing on another. A party may state a single transaction one way or several ways. Rule 8(d)(2) allows a party to “set out two or more statements of a claim or defense alternatively or hypothetically, either in a single count or defense or in separate ones.”³⁵

The two rules divide the work. Rule 8(d) governs how a claim may be stated, and Rule 18(a) governs whether the resulting claims may share a complaint. Elbers shows both at work. He sues Doe Chemical Company for negligently manufacturing a drug. Rule 18(a) allows, but does not require, him to add a strict liability claim based on the same events, and Rule 8(d)(3) authorizes alternative or inconsistent pleading. If he leaves the strict liability claim out, res judicata will bar him from asserting it in a later action.³⁶ That pressure to join is taken up under claim preclusion below.

The rule reaches inconsistent claims as well, so a claimant need not elect a single theory at the pleading stage.³⁷

Marsh's two claims cannot both be proved, because one assumes a binding agreement and the other assumes none. Rule 18(a) still admits both as alternative claims, and the inconsistency is no obstacle.³⁸ Marsh does not have to decide before trial which version of events the factfinder will accept. Two independent claims, such as a claim over the wall and a claim over an unrelated loan, could both succeed, and that marks the difference between the two kinds.

Older practice shows how much freedom the rule created. At common law a plaintiff could join alternative versions of one grievance only by pleading each in a separate count within a single form of action. A count in assumpsit could not sit beside a count in trover, even when both grew out of the same allegedly wrongful taking.³⁹ The common law tied many of its procedural rules to the aim of reducing litigation to the fewest possible issues, a limit the equity courts did not impose.⁴⁰

The word “alternative” also appears in party joinder, where it produces a familiar mix-up.

Here the open choice lies between adversaries, not between theories against one adversary. Whether Kline and Ortega may be sued together is a party-joinder question, and Rule 20(a)(2) answers it: both claims arise out of the same fire and share the common question of who caused it.⁴¹ Rule 18(a) has no say in that decision, because it presupposes that the target of each claim is already an opposing party. The sorting question is whether the choice lies between theories against one opponent, which is Rule 18(a), or between opponents, which is Rule 20(a)(2).

Joining Multiple Claims