This ruling has immediate implications for healthcare providers, insurers, and litigants in states that rely on affidavit-of-merit screening statutes.

On January 20, 2026, the U.S. Supreme Court resolved a sharp divide among federal circuits on whether state law affidavit-of-merit requirements—provisions conditioning the right to pursue a claim on the filing of a supporting expert affidavit with the complaint—apply in federal court diversity cases. In Berk v. Choy, a case arising from a Delaware medical malpractice action, the Court held that such a statute conflicts with Federal Rule of Civil Procedure 8 and therefore does not apply in federal court.

This decision is likely to affect early-case strategy in federal court professional liability cases by reducing threshold dismissals based on a missing affidavit of merit and instead shifting emphasis to federal pleading and, later, merits testing under the Federal Rules of Civil Procedure.

The Circuit Split on Applicability of State Law Affidavit-of-Merit Requirements

Prior to Berk v. Choy, the federal circuits were sharply divided on whether state affidavit-of-merit requirements applied in federal diversity cases. Six courts—the Second, Fourth, Fifth, Sixth, Seventh, and Ninth—have held that such statutes could not be enforced in federal court because they conflict with the Federal Rules. Those courts generally reasoned that the Federal Rules establish what must be filed at the pleading stage and do not permit states to impose additional front-end evidentiary prerequisites as a condition of proceeding. The Third and Tenth Circuits held the opposite, concluding that affidavit-of-merit requirements are substantive and must be enforced in professional malpractice actions.

The split created materially different outcomes depending on where a case was filed or removed. In some circuits, failure to file an affidavit could end the case at the threshold in federal court, while in others the same omission would not be dispositive. This split created uncertainty for litigants and complicated forum-selection and removal decisions.

The Statute Involved in Berk

Delaware law provides that “[n]o health-care negligence lawsuit shall be filed … unless the complaint is accompanied by … [a]n affidavit of merit … signed by an expert witness … stating that there are reasonable grounds to believe that there has been health-care medical negligence committed by each defendant.” 18 Del. C. § 6853(a)(1), (c). If the affidavit does not accompany the complaint or the plaintiff has not filed a timely extension motion, the clerk of court “shall refuse to file the complaint and it shall not be docketed.” Id. § 6853(a)(1).

Harold Berk, a Florida resident, filed a Delaware-law medical malpractice action in federal court after receiving treatment at a Delaware medical facility while visiting the state. Berk filed his complaint and moved for an extension of time to file the required affidavit, which the District Court granted. He was ultimately unable to secure the affidavit and, instead, filed his medical records under seal. The District Court dismissed the case, and the Third Circuit affirmed, concluding that federal courts sitting in diversity must apply the affidavit statute as substantive state law. The Supreme Court granted review to resolve whether Delaware’s affidavit-of-merit requirement applies in federal court in a diversity action notwithstanding the Federal Rules of Civil Procedure.

The Supreme Court Reverses Dismissal of Berk’s Claims

In a 9-0 decision authored by Justice Amy Coney Barrett, the Supreme Court reversed and held that Delaware’s medical-malpractice affidavit-of-merit statute, 18 Del. C. § 6853, does not apply in federal court because it conflicts with Federal Rule of Civil Procedure 8. Justice Ketanji Brown Jackson filed an opinion concurring in the judgment.

The Court’s analysis followed the classic two-step Federal Rules/Erie doctrine analysis of Shady Grove Orthopedic Associates, P.A. v. Allstate Insurance Co., 559 U.S. 393 (2010): first, determine whether a federal rule "answers the question in dispute"; second, if so, determine whether the rule is valid under the Rules Enabling Act.

Step One: Does a Federal Rule Answer the Disputed Question?

The Court framed the disputed question as whether Berk’s lawsuit may be dismissed because his complaint was not accompanied by the affidavit Delaware requires. The Court held that Rule 8 answers that question. Rule 8(a)(2) provides that a complaint need only provide “a short and plain statement of the claim showing that the pleader is entitled to relief." The Court read this as establishing both a floor and a ceiling—by requiring no more than a statement of the claim, Rule 8 establishes “implicitly, but with unmistakable clarity” that evidence is not required at the pleading stage.

Delaware’s statute, by contrast, demands more by requiring an affidavit of merit accompany the complaint, an obligation that the Court characterized as "a prima facie evidentiary requirement." Because Rule 8 and Section 6853 address the same filing-stage sufficiency question—but provide different answers—the Court concluded that Rule 8 displaces Delaware’s affidavit requirement in federal court.

The Court reinforced this conclusion by pointing to Rule 12’s structure. Rule 12(b)(6) provides the only merits-based ground for dismissal at the pleading stage (“failure to state a claim”), and Rule 12(d) restricts reliance on matters outside the pleadings unless the motion is converted to summary judgment.

The Court also rejected two defense theories that have been used in federal courts to enforce state affidavit-of-merit requirements. First, it declined defendants’ attempt to recast Delaware’s affidavit requirement as a freestanding, early evidentiary screen that could support dismissal in federal court, explaining that doing so would effectively rewrite the statute and that summary judgment under Rule 56 already provides the appropriate mechanism to test the sufficiency of evidence. Second, the Court rejected defendants’ reliance on Rule 11(a)’s proviso (that a pleading need not be verified or accompanied by an affidavit “[u]nless a rule or statute specifically states otherwise”), explaining that Rule 11 governs certifications by attorneys and unrepresented parties and that its affidavit/verification language concerns parties’ verification obligations, not affidavits from third-party experts.

Step Two: Is Rule 8 Valid Under the Rules Enabling Act?

Having found a conflict between the state statute and Rule 8, the Court turned to whether Rule 8 is valid under the Rules Enabling Act, which requires that federal rules “not abridge, enlarge or modify any substantive right." 28 U.S.C. § 2072(b). The test is modest: whether the rule "really regulates procedure.” The Court determined that Rule 8 easily satisfies this standard because it "determines what plaintiffs must present to the court about their claims at the outset of litigation"—the manner and means by which rights are enforced, not the rights themselves.

Critically, the Court rejected defendants' argument that this analysis should turn on whether the displaced state law is substantive, not on whether the Federal Rule is valid, stating that "the substantive nature of [a state] law, or its substantive purpose, makes no difference" to the validity analysis. Because Rule 8 "really regulates procedure," it governs, and Delaware's affidavit requirement "does not apply in federal court."

Justice Jackson’s concurrence, while agreeing in the result, found the conflict lies with Rules 3 and 12 rather than Rule 8. In her view, Rule 3’s provision that “[a] civil action is commenced by filing a complaint with the court" directly conflicts with Delaware’s requirement that an affidavit must accompany the complaint before the case can be docketed.

Implications

This ruling has immediate implications for healthcare providers, insurers, and litigants in states that rely on affidavit-of-merit screening statutes. By eliminating a procedural mechanism that often enabled defendants to obtain early dismissal in federal court—or early settlement leverage—without reaching merits discovery, the decision removes a common “gatekeeping” tool and shifts the front-end litigation fight to the Federal Rules’ ordinary tools for evaluating pleadings and proof: Rule 12 (pleading sufficiency), Rule 26 (case management and sequencing), and Rule 56 (summary judgment). Additionally, although Berk arose in the medical-malpractice context, its reasoning is not inherently limited to medical-negligence statutes and may apply to analogous affidavit/certificate-of-merit regimes governing claims against other licensed professionals.

Defendants should expect fewer early dismissals based solely on noncompliance with state screening statutes, with increased emphasis on Rule 12 motions directed to the pleadings, structured early case-management proposals, and litigation plans that develop the expert record for dispositive motions. Plaintiffs’ counsel, meanwhile, may view federal court as a more attractive forum, potentially altering forum-selection and removal strategy, defense-cost timing, and settlement dynamics.

Importantly, Berk governs only federal-court practice; state courts will continue to enforce their own affidavit-of-merit requirements. In jurisdictions where an affidavit requirement functions as a meaningful threshold defense in state court, removal may forfeit that particular early-disposition lever and shift the defense to the Federal Rules’ pleading, scheduling, and dispositive-motion framework. The decision’s practical impact will vary by jurisdiction and by statute—most notably based on when an affidavit must be filed, what consequences follow from noncompliance, and how closely the state regime mirrors Delaware’s “with-the-complaint” model.

For More Information

If you have any questions about this Alert, please contact Robert M. Palumbos, Leah Mintz, April D. Seabrook, any of the attorneys in our Trial Practice Group or the attorney in the firm with whom you are regularly in contact.

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