Does Delaware law, which requires a medical professional's "affidavit of merit" to accompany a medical malpractice complaint, apply in federal court? Specifically, the Court considers whether Del. Code, Tit. 18, § 6853(a)(1) is displaced by the Federal Rules of Civil Procedure. The issue is whether a federal court may dismiss a lawsuit for failure to provide such an affidavit.

• Delaware's affidavit requirement under § 6853 is not enforceable in federal court.
• The requirement is displaced by the Federal Rules of Civil Procedure.

• The affidavit requirement is a "precondition to proceeding" that is consistent with the Federal Rules, citing *Cohen v. Beneficial Industrial Loan Corp.*.
• The law should be viewed as a "free-floating evidentiary requirement" that can serve as a basis for early dismissal rather than a pleading requirement.
• The proviso in Federal Rule of Civil Procedure 11(a) incorporates state affidavit laws like § 6853 because it allows for pleadings to be accompanied by an affidavit if a statute "specifically states otherwise."

• The Court held that Delaware's affidavit law does not apply in federal court because it is displaced by Federal Rule of Civil Procedure 8.
• The Court applied a two-step analysis from *Shady Grove Orthopedic Associates, P. A. v. Allstate Ins. Co.*: first, determine if a Federal Rule answers the disputed question; second, if it does, the Rule governs unless it "exceeds statutory authorization or Congress's rulemaking power."
• The Court found that Rule 8(a)(2) answers the question by requiring only "a short and plain statement of the claim showing that [the pleader] is entitled to relief," which implicitly excludes the requirement of evidence like an affidavit, citing *Hanna v. Plumer*.
• The Court noted that Rule 12(b)(6) and Rule 12(d) reinforce this by limiting merits-based dismissal to "failure to state a claim upon which relief can be granted" and prohibiting courts from considering "matters outside the pleadings."
• The Court rejected the respondents' reliance on *Cohen v. Beneficial Industrial Loan Corp.*, stating that *Cohen* dealt with liability and bonds, not the information required to state a claim at the outset of litigation.
• The Court dismissed the Rule 11(a) argument, ruling that the rule's proviso regarding affidavits refers to verification by the party or attorney, not third-party affidavits, citing *Business Guides, Inc. v. Chromatic Communications Enterprises, Inc.*.
• Regarding the Rules Enabling Act (28 U. S. C. § 2072(b)), the Court held Rule 8 is valid because it "really regulates procedure" under the test in *Sibbach v. Wilson & Co.*.
• The Court emphasized that under *Shady Grove*, the "substantive nature of [a state] law, or its substantive purpose, makes no difference" to the analysis of a Federal Rule's validity.