When State Procedure Meets Federal Rules: Berk v. Choy and the Boundaries of Federal Civil Practice

By Arjan Bir Sodhi

Federal courts are often asked to resolve disputes rooted entirely in state law. When they do, they must navigate a familiar but delicate problem: determining whether state procedural requirements apply in federal court. The Supreme Court’s recent decision in Berk v. Choy revisits that tension and offers a clear reaffirmation of a foundational principle of federal civil procedure. When a valid Federal Rule of Civil Procedure directly addresses an issue, it governs, even if a state rule points in another direction.

The case arose from a medical malpractice claim governed by Delaware law but filed in federal court under diversity jurisdiction. Delaware, like many states, requires plaintiffs in medical malpractice cases to submit an affidavit of merit from a medical professional attesting that the claim has a reasonable basis. The question before the Court was not whether Delaware may impose that requirement in its own courts, but whether federal courts must enforce it when a plaintiff invokes federal jurisdiction.

The core issue in Berk v. Choy was whether Delaware’s affidavit-of-merit statute applies in federal court, or whether it is displaced by the Federal Rules of Civil Procedure under the Rules Enabling Act. Put differently, the Court was asked to decide whether a state-law precondition to suit could override the federal pleading and dismissal framework.

The analysis is governed by a familiar sequence of cases beginning with Erie Railroad Co. v. Tompkins, continuing through Hanna v. Plumer, and refined in Shady Grove Orthopedic Associates v. Allstate Insurance Co. Under that framework, state substantive law generally applies in federal court, but a valid Federal Rule of Civil Procedure displaces conflicting state law when the Rule answers the same question and regulates procedure rather than substance. The Rules Enabling Act authorizes federal rules so long as they govern the manner and means of enforcing rights, not the rights themselves. Sibbach v. Wilson & Co. makes clear that the inquiry focuses on what the federal rule regulates, not on whether the state rule has substantive effects.

The majority concluded that Federal Rule of Civil Procedure 8 answers the relevant question. Rule 8 requires only a short and plain statement showing that the pleader is entitled to relief. By design, it does not require evidentiary submissions at the pleading stage. That principle is reinforced by Rule 12, which limits dismissal to failures to state a claim and prohibits courts from considering matters outside the pleadings when resolving Rule 12(b)(6) motions.

Delaware’s affidavit requirement, by contrast, conditions the viability of a complaint on the submission of an expert affidavit. Even if characterized as a screening mechanism rather than a pleading rule, the effect is the same: a complaint that otherwise satisfies Rule 8 may be dismissed solely because it lacks evidence. The Court rejected attempts to reframe the affidavit requirement as a free-floating evidentiary rule, noting that the Federal Rules already provide mechanisms, such as summary judgment, for testing evidentiary sufficiency at later stages of litigation.

Because Rule 8 directly addresses what a plaintiff must submit at the outset of a case, and because it is a valid procedural rule under the Rules Enabling Act, it displaces Delaware’s affidavit statute in federal court. The Third Circuit’s contrary conclusion was therefore reversed.

Justice Jackson agreed with the judgment but offered a narrower and, in her view, cleaner path to the same result. Rather than grounding the conflict in Rule 8, she focused on Rules 3 and 12.

Rule 3 provides that a civil action is commenced by filing a complaint with the court, full stop. Delaware law, however, directs court clerks to refuse to file and docket a medical malpractice complaint unless it is accompanied by an affidavit of merit or a motion for an extension. That, Justice Jackson explained, creates a direct conflict about what is required to commence an action. When a Federal Rule answers that question, state law must give way.

She also emphasized Rule 12(d), which forbids courts from considering matters outside the pleadings when deciding a motion to dismiss. Delaware’s statute, as interpreted by the Delaware Supreme Court, requires courts to evaluate the presence or sufficiency of an affidavit when determining whether a case may proceed. Because an affidavit of merit is plainly outside the pleadings, Rule 12 independently bars enforcement of the state requirement in federal court.

Justice Jackson cautioned against characterizing the affidavit as both part of the pleadings and outside them depending on the analytical step. In her view, recognizing the conflicts with Rules 3 and 12 avoided distorting the purpose of Rule 8 and preserved doctrinal coherence.

Consider a plaintiff injured during a hospital stay who sues a physician for malpractice. If the plaintiff files in Delaware state court, failure to include an affidavit of merit may prevent the case from being docketed at all. If the same plaintiff files in federal court under diversity jurisdiction, however, Rule 3 requires the clerk to docket the case upon receipt of the complaint. Rule 8 governs the content of that complaint, and Rule 12 governs whether it may be dismissed. Under Berk v. Choy, the federal court may not impose an additional state-law evidentiary hurdle at the pleading stage, even if that hurdle would apply in state court.

Berk v. Choy reinforces a central principle of federal civil procedure: uniform federal rules govern federal courts, even when state law takes a different procedural approach. The decision does not invalidate state affidavit-of-merit statutes. It simply confirms that such statutes cannot override the Federal Rules when a case is properly before a federal court.

For litigators, the case underscores the strategic and doctrinal significance of forum selection. For courts, it reaffirms the continuing vitality of the Rules Enabling Act framework and the Court’s longstanding refusal to allow state procedural requirements to fragment federal practice. And for students of civil procedure, it serves as a modern illustration of how Erie, Hanna, and Shady Grove continue to shape the everyday mechanics of federal litigation.

References

• Berk v. Choy, 607 U.S. ___ (2026).

• Shady Grove Orthopedic Assocs., P.A. v. Allstate Ins. Co., 559 U.S. 393 (2010).

• Hanna v. Plumer, 380 U.S. 460 (1965).

• Erie R.R. Co. v. Tompkins, 304 U.S. 64 (1938).

• Sibbach v. Wilson & Co., 312 U.S. 1 (1941).

• Bell Atl. Corp. v. Twombly, 550 U.S. 544 (2007).