What is the core rule of the Erie doctrine for federal courts sitting in diversity?

What is the core rule of the Erie doctrine for federal courts sitting in diversity?

• A. Apply state procedural law and federal substantive law.
• B. Apply federal substantive law and state procedural law.
• C. Apply state substantive law and federal procedural law.
• D. The court may choose either depending on policy.

Answer: (C)

In diversity cases, the goal is to keep the outcome of the case aligned with state law while using uniform federal rules to run the litigation. The essential rule is that a federal court sitting in diversity applies the state's substantive law—rights, duties, remedies, and the elements of the claim—while applying the federal procedural rules that govern how the case is litigated. This keeps substantive rights determined by the state’s policy and law, but ensures the mechanics of the case (pleading, discovery, trial procedure) are guided by the Federal Rules of Civil Procedure and related federal rules. For example, the test for liability and the applicable statute of limitations come from the forum state's substantive law, whereas how discovery is conducted, how motions are raised, and how trials proceed follow federal procedure. There are nuanced exceptions in some situations, but the basic rule is state substantive law and federal procedural law.

In diversity cases, the goal is to keep the outcome of the case aligned with state law while using uniform federal rules to run the litigation. The essential rule is that a federal court sitting in diversity applies the state's substantive law—rights, duties, remedies, and the elements of the claim—while applying the federal procedural rules that govern how the case is litigated. This keeps substantive rights determined by the state’s policy and law, but ensures the mechanics of the case (pleading, discovery, trial procedure) are guided by the Federal Rules of Civil Procedure and related federal rules.

For example, the test for liability and the applicable statute of limitations come from the forum state's substantive law, whereas how discovery is conducted, how motions are raised, and how trials proceed follow federal procedure. There are nuanced exceptions in some situations, but the basic rule is state substantive law and federal procedural law.