Whether a state law 'affidavit of merit' requirement applies in a federal court medical-negligence case governed by state substantive law

QUESTION PRESENTED Many states require an “affidavit of merit” to accompany a complaint asserting a claim of medical negligence. The circuits are divided about whether this requirement applies to an action brought in federal court that is governed by state substantive law. The Sixth and Ninth Circuits view state law “affidavit of merit” requirements as preempted by the Federal Rules of Civil Procedure in accordance with the decision of this Court in Shady Grove Orthopedic Associates, PA. v. Allstate Insurance Co., 559 U.S. 393 (2010). The Third, Fourth, Eighth and Tenth Circuits follow a different rule, routinely applying state law “affidavit of merit” statutes to dismiss any complaint that is not supported by the state law affidavit. The Seventh Circuit in this case deepened the split by siding with the circuits that apply a state law in federal court and treating the Illinois requirement for an “affidavit of merit” as an affirmative defense that a defendant may raise in a motion for summary judgment. The question presented is: In adjudicating a medical negligence claim brought in federal court that is governed by state substantive law, must a district court apply a state law “affidavit of merit” requirement or is such a requirement preempted by the Federal Rules of Civil Procedure? @