# MBE Civil Procedure Erie Doctrine: Substantive vs Procedural Trap

Canonical: https://www.barprepplay.com/mbe/civil-procedure/erie-substantive-vs-procedural/
Subject: Civil Procedure
Byline: BarPrepPlay
Last reviewed: April 21, 2026

## Fact pattern

Marisol, an Indiana citizen, files a diversity suit in the Southern District of Indiana against Pace Logistics, an Illinois LLC, for a warehouse fire in Illinois that destroyed $200,000 of her inventory. Indiana has a borrowing statute that requires Indiana courts to apply the shorter of Indiana's or the foreign jurisdiction's statute of limitations. Illinois's SoL for property damage is two years; Indiana's is four. Marisol files three years after the fire. Indiana also has a statute that requires plaintiffs in commercial fire-loss cases to post a $5,000 bond before discovery may begin. Pace moves to dismiss as time-barred and, in the alternative, to require the bond. The federal court must decide which Indiana rules to apply.

## Quick answer

The federal court must apply both the Indiana borrowing statute (dismissing the case as time-barred under Illinois's two-year SoL) and the Indiana pre-discovery bond requirement. Under Erie, a federal court sitting in diversity applies state substantive law and federal procedural law. Statutes of limitations are substantive under Guaranty Trust v. York because they are outcome-determinative; borrowing statutes are part of the state's SoL machinery and travel with it. Where a state rule conflicts with a Federal Rule of Civil Procedure on point, Hanna v. Plumer applies the Federal Rule so long as it is valid under the Rules Enabling Act. For state rules with no Federal Rule on point, courts apply the modified outcome-determinative test under Byrd and Hanna, asking whether ignoring the state rule would encourage forum shopping or cause inequitable administration of the laws.

## Issue

Sitting in diversity, must the federal court apply (a) Indiana's borrowing statute (which would import Illinois's shorter SoL and bar the case) and (b) Indiana's pre-discovery bond requirement?

## Rule

Under Erie, a federal court sitting in diversity applies state substantive law and federal procedural law. Statutes of limitations are substantive under Guaranty Trust v. York because they are outcome-determinative; borrowing statutes are part of the state's SoL machinery and travel with it. Where a state rule conflicts with a Federal Rule of Civil Procedure on point, Hanna v. Plumer applies the Federal Rule so long as it is valid under the Rules Enabling Act. For state rules with no Federal Rule on point, courts apply the modified outcome-determinative test under Byrd and Hanna, asking whether ignoring the state rule would encourage forum shopping or cause inequitable administration of the laws.

## Application

The Indiana borrowing statute is part of Indiana's SoL framework. Statutes of limitations are substantive under Guaranty Trust because their application changes the case outcome, and a borrowing statute is just the choice-of-SoL component of the same machinery. The federal court must therefore apply Indiana's borrowing statute, which imports Illinois's two-year SoL. Marisol's suit is filed three years after the fire, so the case is time-barred. The Indiana pre-discovery bond rule is a closer call. There is no Federal Rule of Civil Procedure that requires plaintiffs to post a bond before discovery, so Hanna does not displace it. The bond is plainly outcome-determinative — if Marisol cannot post $5,000, discovery never begins and her case dies — and refusing to apply it would invite forum shopping into federal court to escape state-law cost barriers. Under the twin aims of Erie, the federal court must apply the bond requirement.

## Conclusion

The federal court must apply both the Indiana borrowing statute (dismissing the case as time-barred under Illinois's two-year SoL) and the Indiana pre-discovery bond requirement.

## Numbered reasoning steps

1. Confirm subject-matter jurisdiction is diversity, which triggers the Erie analysis.
2. Identify each contested rule separately and ask whether it is substantive or procedural.
3. For the SoL, apply Guaranty Trust's outcome-determinative test — SoLs and their borrowing statutes are substantive.
4. For the bond rule, ask whether a Federal Rule occupies the field; if not, run the modified outcome-determinative + twin-aims test.
5. Reach a separate Erie conclusion for each rule before stating the combined disposition.

## Why wrong answers fail

- Federal procedural rules always govern in federal court, so Indiana's SoL does not apply.: That ignores Erie. The Rules of Decision Act requires the federal court to follow state substantive law, and SoLs are substantive under Guaranty Trust.
- FRCP 1 is a Federal Rule on point, so it displaces Indiana's bond requirement.: FRCP 1 is a general aspirational provision about the just and speedy administration of all rules. It does not occupy the specific field of pre-discovery bonds, so Hanna does not apply.
- Statutes of limitations are procedural and are governed by federal law in diversity.: Guaranty Trust v. York held the opposite — SoLs are substantive for Erie purposes because they are outcome-determinative.
- Indiana's borrowing statute is choice-of-law and not within Erie's scope.: A diversity court applies the choice-of-law rules of the forum state under Klaxon. The borrowing statute is part of Indiana's SoL machinery and rides along with the SoL itself.

## Issue-spotting checklist

- Confirm jurisdiction is diversity before invoking Erie at all.
- Treat each disputed rule individually — never lump them together.
- Ask first whether a Federal Rule of Civil Procedure or federal statute is on point; if yes, follow Hanna.
- For pure state rules with no Federal Rule conflict, apply outcome-determinative + twin-aims under Byrd and Hanna.
- Remember that borrowing statutes, presumptions, and burdens of proof are typically substantive.

## Primary law and source anchors

- **Erie R.R. v. Tompkins, 304 U.S. 64 (1938)**: Federal courts in diversity apply state substantive law; there is no general federal common law.
- **Guaranty Trust Co. v. York, 326 U.S. 99 (1945)**: Statutes of limitations are substantive for Erie purposes because they are outcome-determinative.
- **Hanna v. Plumer, 380 U.S. 460 (1965)**: A valid Federal Rule of Civil Procedure on point governs even when it conflicts with state law.
- **28 U.S.C. § 1652 (Rules of Decision Act)**: The laws of the several states are rules of decision in federal civil actions, except where federal law otherwise provides.

## 3-question quiz teaser

1. A federal court sitting in diversity must apply which of the following from the forum state?
  - Federal procedural rules in all instances
  - State substantive law, including statutes of limitations
  - Only state choice-of-law rules
  - Only state evidentiary rules
2. Under Hanna v. Plumer, what controls when a state rule conflicts with a valid Federal Rule of Civil Procedure on point?
  - The state rule, because federalism favors deference
  - The Federal Rule, because it is valid under the Rules Enabling Act
  - Whichever is more recent
  - The forum state's choice-of-law rules
3. A state borrowing statute that imports a shorter foreign SoL is best characterized as:
  - Procedural and disregarded by federal diversity courts
  - Substantive because it is part of the state's SoL machinery
  - Federal common law to be developed by the federal court
  - Constitutional rather than statutory in character

## Related pages

- [MBE Civil Procedure Personal Jurisdiction Trap Example](https://www.barprepplay.com/mbe/civil-procedure/personal-jurisdiction-saas-trap/)
- [MBE Contracts Offer and Acceptance Sample Fact Pattern + Model Answer](https://www.barprepplay.com/mbe/contracts/offer-acceptance-mailbox-rule/)

## Gated app actions

- [Take the 3-question quiz](https://www.barprepplay.com/?seo_slug=erie-substantive-vs-procedural&seo_action=quiz)
- [Open a related Civ Pro drill](https://www.barprepplay.com/?seo_slug=erie-substantive-vs-procedural&seo_action=drill)
- [Found an issue?](https://www.barprepplay.com/?seo_slug=erie-substantive-vs-procedural&seo_action=report)