Whether federal or Ohio preclusion law governs the effect of the prior Ohio judgment in the later federal action.
Holding
Ohio preclusion law governs, because 28 U.S.C. § 1738 requires federal courts to give an Ohio judgment the same preclusive effect it would receive in Ohio courts.
Reasoning
The court distinguished claim preclusion from issue preclusion. Claim preclusion bars a later action on the same claim after a final merits judgment and can also bar claims that should have been raised earlier. Issue preclusion bars relitigation only of issues that were actually litigated, decided, and necessary to the earlier judgment.
Under the Full Faith and Credit Act, federal courts must generally apply the rendering state's law to determine the preclusive effect of a state-court judgment. The Supreme Court's decision in Marrese v. American Academy of Orthopaedic Surgeons makes that rule applicable even when the later claim falls within the exclusive jurisdiction of federal courts.
Accordingly, the Sixth Circuit could not decide the question by applying a free-standing federal rule of claim preclusion. It first had to ask whether Ohio itself would treat the Franklin County judgment as precluding a subsequent action on Gargallo's federal securities claims.