Brief of Professor Michael T. Morley as Amicus Curiae in Support of Respondents, Berk v. Choy, No. 24-440 (U.S. filed Aug. 5, 2025)

The Federal Rules of Civil Procedure do not displace Delaware's affidavit of merit requirement. Under the Rules of Decision Act, 28 U.S.C. § 2072(a), the Court has the authority to promulgate procedural rules. At the same time, § 2072(b) limits that authority by prohibiting rules that “abridge, enlarge or modify any substantive rights.” Section 2072 thus establishes two distinct requirements. Even if a rule is procedural, or rationally capable of being classified as such, § 2072(b) mandates that it may not change a substantive right.&nbsp; A procedural rule that validly applies in one case because it does not change a substantive right cannot be applied in other cases where its application would affect substantive rights.<br><br>There are various potential tests for determining when a procedural rule impacts substantive rights. <i>Erie Railroad Co. v. Tompkins</i>, 304 U.S. 64, 78-79 (1938), offers one possible standard, deeming a law substantive if its application “significantly affects” the outcome of litigation. <i>Gasperini v. Ctr. for Humanities, Inc.</i>, 518 U.S. 415, 416 (1996).&nbsp; Another is to evaluate the law under Federal Rule of Civil Procedure 1, treating a right as procedural if it is aimed at securing “the just, speedy, and inexpensive determination” of federal cases, Fed. R. Civ. P. 1, and substantive if it furthers other, unrelated goals.&nbsp; A third approach is to deem a rule substantive if it “substantially affect[s] . . . primary decisions” made outside the litigation context.&nbsp; <i>Hanna v. Plumer</i>, 380 U.S. 460, 476 (1965) (Harlan, J., concurring).&nbsp; A fourth option is to ask whether the rule at issue is generally applicable to civil actions, in which case it is procedural, or instead “specially” affects “a group of litigants or prospective litigants,” in which case it is substantive. Paul D. Carrington, <i>“Substance” and “Procedure” in the Rules Enabling Act</i>, 1989 Duke L.J. 281, 308 (1989).<br><br>Under any of these tests, Delaware’s affidavit of merit requirement creates substantive rights.&nbsp; The requirement—which obliges a plaintiff to submit with a complaint alleging a medical malpractice claim an expert affidavit attesting to the merit of the claim, Del. Code Ann. tit. 18, § 6853(a)—determines whether a person is entitled to sue at all, not merely how a person must initiate a lawsuit.&nbsp; The rule substantially affects the outcome of litigation, since failure to comply with it results in dismissal. The rule is not generally applicable to civil actions; it applies only to medical malpractice claims.&nbsp; The requirement is not aimed solely at resolving cases justly and inexpensively; its function is to protect medical providers by precluding some medical malpractice claims.&nbsp; Those additional protections affect conduct outside the courtroom by allowing medical providers to act with less fear of litigation.&nbsp; Accordingly, the Federal Rules do not displace the Delaware affidavit requirement.