Impleader trips up bar takers every single year. The concept sounds simple until you’re staring at a fact pattern where three parties are pointing fingers at each other, and you can’t figure out who’s suing whom or whether the court even has jurisdiction over the new claim.

Let’s fix that.

What Impleader Actually Is (And Why It Matters on the MBE)

Impleader is a procedural device that allows a defending party — most commonly a defendant — to bring a third party into the lawsuit. The governing rule is Federal Rule of Civil Procedure 14, which is why you’ll hear this called “impleader under Rule 14” in virtually every Civil Procedure course and on the bar exam.

Here’s the key concept you need to tattoo on your brain: impleader is not just about adding someone new to the case. It’s specifically about shifting liability. The defendant is saying, in effect, “Even if I’m liable to the plaintiff, this third party is liable to me for all or part of that judgment.”

That distinction matters enormously. The MBE will test whether you understand the difference between a defendant who wants to implead someone and a defendant who simply wants to add a new party for unrelated reasons. Rule 14 only covers the former.

The Elements of Impleader Under Rule 14

When you see impleader under Rule 14 on the bar exam, run through these elements:

1. The impleading party must be a defending party. Usually this is the original defendant, but a third-party defendant who faces claims from another direction can also implead additional parties. The plaintiff generally cannot use Rule 14 to bring in a third party — at least not in the same way.

2. The claim must be for derivative liability. This is the big one. The third-party defendant must be someone who “is or may be liable” to the original defendant for the claim against the defendant. The liability must be derivative — meaning it flows from the same underlying claim the plaintiff has asserted. Think indemnification, contribution, or subrogation.

Classic example: A plaintiff sues a general contractor for construction defects. The general contractor impleads the subcontractor, arguing that if the general contractor is found liable to the plaintiff, the subcontractor owes the general contractor indemnification. That’s textbook Rule 14.

What doesn’t work: The general contractor tries to implead someone who owes it money on a completely unrelated contract dispute. That’s not derivative liability. That’s a separate lawsuit.

3. Timing — the 14-day window. A defendant may serve a third-party complaint without leave of court if it does so within 14 days of serving its original answer. After that, the defendant needs leave of court. The court has discretion to grant or deny that leave, and it will consider factors like prejudice to existing parties, complication of the issues, and delay.

4. The third-party defendant’s options. Once brought in, the third-party defendant has real procedural firepower. It can:

And here’s a detail that shows up on the MBE: the original plaintiff can then assert claims directly against the third-party defendant — but only if those claims arise out of the same transaction or occurrence as the original claim.

Jurisdiction Over Third-Party Claims

This is where impleader under Rule 14 gets genuinely tricky on the bar exam, and where students lose points they shouldn’t.

When a defendant impleads a third party, the court needs a basis for jurisdiction over that new claim. In federal court, this typically comes through supplemental jurisdiction under 28 U.S.C. § 1367. Because the third-party claim is derivative of the original claim, it almost always arises from the same common nucleus of operative fact. That means supplemental jurisdiction usually covers it without any problem.

But here’s the trap the MBE loves to set: the diversity jurisdiction limitation on supplemental jurisdiction.

In a diversity case, supplemental jurisdiction does not extend to claims by plaintiffs against persons made parties under Rule 14 if exercising that jurisdiction would destroy complete diversity. Read that again carefully. The restriction applies to claims by the plaintiff against the third-party defendant — not to the original defendant’s third-party claim itself.

So in a diversity case: the defendant impleads a third-party defendant → supplemental jurisdiction covers that just fine. But if the plaintiff then tries to assert a direct claim against that third-party defendant, and doing so would destroy complete diversity → no supplemental jurisdiction, and the plaintiff needs an independent basis for federal jurisdiction.

This is a nuanced point. The MBE will present a fact pattern where everything looks fine on the surface, and then bury the jurisdictional wrinkle in the details of who is a citizen of what state.

A Sample Fact Pattern to Test Yourself

Here’s the kind of scenario you should be able to work through cold:

A plaintiff, a citizen of Ohio, sues a defendant corporation incorporated in Delaware with its principal place of business in Michigan, alleging $150,000 in damages arising from a defective product. The defendant, believing its supplier caused the defect, files a third-party complaint against the supplier, a citizen of Michigan. The plaintiff then asserts a direct claim against the supplier for $90,000.

Work through it:

Work through every layer. Don’t stop at the first “looks fine” conclusion.

Common Mistakes on the Bar Exam

Confusing impleader with joinder. Impleader under Rule 14 is specifically about derivative liability. If a defendant just wants to add someone who might be liable directly to the plaintiff, that’s not Rule 14 — that might be a question of compulsory or permissive joinder under Rule 19 or 20.

Forgetting the timing rule. The 14-day window is a favorite MBE detail. If the defendant misses it, leave of court is required. The answer choice that says the third-party complaint was improper because no leave was sought — when the defendant filed on day 20 — is correct.

Missing the supplemental jurisdiction trap. As explained above, the plaintiff’s direct claim against a third-party defendant in a diversity case requires independent analysis. Don’t assume supplemental jurisdiction automatically covers everything once Rule 14 is invoked.

Thinking the plaintiff can’t touch the third-party defendant. The plaintiff can assert claims against the third-party defendant — but only if those claims arise from the same transaction or occurrence as the original action, and subject to the jurisdictional limits discussed above.

The FlashTables Connection

FlashTables is a set of professionally formatted two-column PDF rule tables covering all seven MBE subjects — 704 rules total, organized by the official NCBE Subject Matter Outline. The impleader rule, the supplemental jurisdiction limitation in diversity cases, and the interplay between Rule 14 and 28 U.S.C. § 1367 are all laid out side-by-side in the Civil Procedure table, making it easy to see exactly how these rules connect. Whether you’re a law student locking in Civil Procedure for your final outline or a bar taker drilling active recall in the final weeks before the MBE, having these rules in a clean, scannable format at getflashtables.com means you’re reviewing the right rules in the right structure — not hunting through a 400-page outline trying to find the one sentence that matters.

Key Takeaways: What to Memorize for Impleader Under Rule 14

Before you walk into the MBE, make sure you can answer these without hesitation:

Get these elements locked in, and impleader becomes one of the more manageable Rule 14 topics on the MBE. The rule has a clear structure. The exam tests whether you actually know it.