McCarthy v. Hernandez: Limiting AEDPA Habeas Relief over Seibert Instructions

This Supreme Court opinion reverses a lower court's decision to grant habeas corpus relief to Pedro Hernandez, who was convicted for the 1979 murder of Etan Patz. The Second Circuit had previously ruled that the trial judge erred by failing to instruct the jury on legal attenuation regarding the defendant's multiple confessions. However, the Supreme Court determined that the Antiterrorism and Effective Death Penalty Act (AEDPA) restricts federal courts from overturning state convictions unless a "clearly established" federal law was violated. The justices clarified that the precedent in Missouri v. Seibert governs judicial decisions on evidence admissibility rather than jury instructions. Since the New York state courts followed their own procedural laws regarding what juries must consider, the federal appellate court exceeded its authority by imposing a new constitutional requirement. Ultimately, the Court maintains that there is no federal mandate requiring a jury to evaluate the voluntariness or legality of confessions once a judge has admitted them into evidence.