2026 transition tracked · Legacy UBE + NextGen UBESee the latest bar exam updates

Parties and claims · complete doctrine guide

Counterclaims, crossclaims, joinder of claims, and permissive joinder of parties

This module sorts out which of a party's own claims the rules force it to bring now, which it may bring or hold back, and when unrelated people can end up on the same side of one case. A counterclaim is compulsory, and lost if not raised, when it arises from the same transaction or occurrence as the opposing party's claim and does not require joining a party the court cannot reach; it is merely permissive, and can wait for another suit, whenever that same-transaction link is missing. A crossclaim runs between coparties rather than against an opponent, and it is available whenever it arises from the same transaction as the original action or a counterclaim, or relates to the same property. Once parties are already adverse, Rule 18 lets them join as many claims against each other as they wish, related or not, while Rule 20 lets new parties join when their claims share a common question arising from the same transaction or series of transactions.

TESTED STATUSCurrent MBE, MEE where applicable, and NextGen foundational doctrine
01 · COMPLETE FRAMEWORK

Black-letter propositions

  1. 01

    A pleading must state as a compulsory counterclaim any claim the pleader has against an opposing party at the time of service if the claim arises out of the transaction or occurrence that is the subject matter of the opposing party's claim and does not require adding a party over whom the court cannot acquire jurisdiction; the pleader need not state it if it was the subject of another pending action when the action began.

  2. 02

    A pleading may state as a permissive counterclaim any claim against an opposing party that is not compulsory, and a counterclaim need not diminish or defeat the opposing party's recovery, so it may seek relief that exceeds in amount or differs in kind from the relief sought against the pleader.

  3. 03

    A pleading may state as a crossclaim any claim by one party against a coparty if it arises out of the transaction or occurrence that is the subject matter of the original action or of a counterclaim, or relates to property that is the subject matter of the original action, and it may claim that the coparty is or may be liable for all or part of a claim asserted against the crossclaimant.

  4. 04

    Rule 18(a) lets a party asserting a claim, counterclaim, crossclaim or third-party claim join as many claims as it has against an opposing party, related or not, and Rule 18(b) permits contingent claims to be joined, though the court grants relief only according to the parties' substantive rights.

  5. 05

    Persons may join as plaintiffs, or be joined as defendants, if any right to relief is asserted jointly, severally or in the alternative with respect to the same transaction, occurrence or series of transactions or occurrences and a question of law or fact common to all of them will arise in the action.

  6. 06

    Under Rule 20(a)(3), a plaintiff or defendant need not be interested in obtaining or defending against all the relief demanded, and Rule 20(b) lets the court issue protective orders, including for separate trials, to protect a party from embarrassment, delay, expense or other prejudice.

  7. 07

    For convenience, to avoid prejudice, or to expedite and economize, the court may order a separate trial of one or more issues, claims, crossclaims, counterclaims or third-party claims under Rule 42(b), and it must preserve any federal right to a jury trial; the court may also consolidate actions that involve a common question of law or fact.

  8. 08

    Supplemental jurisdiction under 28 U.S.C. section 1367(a) covers claims so related to the claims in the action within original jurisdiction that they form part of the same case or controversy, including claims involving joinder or intervention of additional parties, which is why a compulsory counterclaim needs no independent basis of jurisdiction.

02 · ORDER OF ANALYSIS

Use this attack sequence under time

1

Frame the issue

Identify each claim between the parties and ask whether it arises out of the same transaction or occurrence as the opposing party's claim.

2

Resolve the next checkpoint

Decide whether the claim is a compulsory counterclaim, a permissive counterclaim, or a crossclaim against a coparty.

3

Resolve the next checkpoint

For joinder of parties, test the same-transaction requirement and the common question requirement.

4

Finish the conclusion

Ask whether subject-matter jurisdiction supports each added claim, and whether separate trials or consolidation are warranted.

03 · DISTINCTIONS THAT CREATE POINTS

Common wrong turns

  • Rule 18 lets a party join unrelated claims against the same opposing party, but Rule 20 does not let a plaintiff sue unrelated defendants together.
  • A crossclaim runs between coparties and needs a connection to the original action, and a claim against an opposing party is a counterclaim.
  • A counterclaim may seek more than the plaintiff's claim is worth, and it does not have to reduce the plaintiff's recovery.
04 · WORKED APPLICATION

Worked example

A driver is sued for damages after a collision. He was also injured in the collision and, separately, the plaintiff owes him money on an unrelated loan.

Model analysis

His injury claim arises from the same collision and must be stated as a compulsory counterclaim. The unrelated loan claim is a permissive counterclaim that he may add, and Rule 18(a) would let him join further claims against the plaintiff, subject to subject-matter jurisdiction.

05 · CLOSED-BOOK RETRIEVAL

Practice this topic

06 · FROM THE PRIMARY TEXT

Counterclaims and crossclaims

Federal Rule of Civil Procedure 13(a) requires a pleading to state as a counterclaim any claim the pleader has against an opposing party at the time of service if it arises out of the transaction or occurrence that is the subject matter of the opposing party's claim and does not require adding another party over whom the court cannot acquire jurisdiction. Exceptions apply if the claim was the subject of another pending action when the action began, or if the opposing party sued by attachment or other process that did not establish personal jurisdiction over the pleader and the pleader asserts no counterclaim.

Rule 13(b) allows any claim that is not compulsory to be stated as a permissive counterclaim, and Rule 13(c) says a counterclaim need not diminish or defeat the recovery sought and may request relief that exceeds in amount or differs in kind. Rule 13(g) allows a crossclaim against a coparty if it arises out of the transaction or occurrence that is the subject matter of the original action or of a counterclaim, or relates to property that is the subject of the action, and Rule 13(h) says Rules 19 and 20 govern adding a party to a counterclaim or crossclaim.

07 · FROM THE PRIMARY TEXT

Joinder of claims and parties

Rule 18(a) allows a party asserting a claim, counterclaim, crossclaim or third-party claim to join as independent or alternative claims as many claims as it has against an opposing party. Rule 18(b) allows joinder of contingent claims, and it gives the example of a plaintiff stating a claim for money and a claim to set aside a fraudulent conveyance without first obtaining a money judgment.

Rule 20(a)(1) lets persons join as plaintiffs if they assert a right to relief jointly, severally or in the alternative arising out of the same transaction, occurrence or series of transactions or occurrences and a common question of law or fact will arise. Rule 20(a)(2) states the same test for joining defendants, and Rule 20(a)(3) says a party need not be interested in all the relief demanded, so the court may enter judgment for or against fewer than all parties according to their rights and liabilities.

08 · FROM THE PRIMARY TEXT

Protective orders, separate trials, and supplemental jurisdiction

Rule 20(b) authorizes orders, including for separate trials, to protect a party from embarrassment, delay, expense or other prejudice arising from including a person against whom the party asserts no claim. Rule 42(a) lets a court join for hearing or trial, or consolidate, actions that involve a common question of law or fact, and Rule 42(b) lets it order a separate trial of issues, claims, crossclaims, counterclaims or third-party claims for convenience, to avoid prejudice, or to expedite and economize, while preserving any federal right to a jury trial.

Twenty-eight U.S.C. section 1367(a) gives district courts supplemental jurisdiction over all other claims so related to the claims within original jurisdiction that they form part of the same case or controversy under Article III, including claims involving joinder or intervention of additional parties. Subsection (b) limits that power in diversity-only cases for claims by plaintiffs against persons joined under Rules 14, 19, 20 or 24.

09 · QUICK ANSWERS

Frequently asked questions

What is the controlling rule for counterclaims, crossclaims, joinder of claims, and permissive joinder of parties?+

Classify each claim as compulsory, permissive or crossclaim, apply the same-transaction test, check joinder of parties under Rule 20, and address jurisdiction and separate trials.

What makes a counterclaim compulsory?+

It arises out of the transaction or occurrence that is the subject of the opposing party's claim and does not require adding a party over whom the court lacks jurisdiction, under Rule 13(a).

Can a counterclaim seek more than the plaintiff's claim?+

Yes. Rule 13(c) says it may request relief that exceeds in amount or differs in kind from the relief sought against the pleader.

What is a crossclaim?+

A claim by one party against a coparty that arises out of the transaction or occurrence in the original action or a counterclaim, under Rule 13(g).

May a plaintiff sue unrelated defendants in one action?+

No. Rule 20(a)(2) requires a right to relief arising out of the same transaction or occurrence and a common question of law or fact.

SOURCE DESK

Primary sources

Federal Rule of Civil Procedure 13, Cornell LII↗Federal Rule of Civil Procedure 18, Cornell LII↗Federal Rule of Civil Procedure 20, Cornell LII↗Federal Rule of Civil Procedure 42, Cornell LII↗28 U.S.C. section 1367, Cornell LII↗

Governing text for counterclaims, crossclaims, joinder of claims, and permissive joinder of parties

Federal Rules of Civil Procedure (U.S. Courts) ↗