Whether federal law required a state trial court to instruct a jury on the rule of attenuation when determining if later confessions should be disregarded due to an initial involuntary confession. Specifically, whether the Second Circuit erred under 28 U.S.C. § 2254(d)(1) by granting habeas relief based on *Missouri v. Seibert*. The core issue is whether a trial court's refusal to explain attenuation to a jury constitutes a violation of clearly established federal law.

• The Second Circuit exceeded its authority under the Antiterrorism and Effective Death Penalty Act of 1996 (AEDPA).
• No clearly established federal law required the trial court to instruct the jury on attenuation.
• Federal habeas courts may not disturb state convictions based on doubts about the reliability of confessions or misinterpretations of state law.

• The trial court's response to the jury note violated clearly established federal law by failing to explain the rule adopted by Justice Kennedy in *Missouri v. Seibert*.
• Because New York law allows juries to assess whether statements were "involuntarily made" under N.Y. Crim. Proc. Law Ann. § 710.70(3), the rule of attenuation must control that consideration.
• The failure to provide this instruction denied him due process because the legality of the confessions was central to the trial.

• The Court held that the Second Circuit exceeded its authority under 28 U.S.C. § 2254(d)(1) because no clearly established federal law required the trial court to instruct the jury on attenuation.
• Under 28 U.S.C. § 2254(d)(1), habeas relief is only available if a state court decision was "contrary to, or involved an unreasonable application of, clearly established Federal law."
• The Court noted that unlike New York law, the Federal Constitution does not "require that both judge and jury pass upon the admissibility" or voluntariness of evidence when constitutional grounds are asserted for exclusion, citing *Lego v. Twomey*.
• Regarding *Missouri v. Seibert*, the Court reasoned that this case concerned a trial court's ruling on a suppression motion rather than a jury's assessment of attenuation.
• The Court found no precedent holding that the Due Process Clause requires a trial court to explain an issue to a jury that the jury is not required to decide, citing *Estelle v. McGuire* and *Cupp v. Naughten*.
• The Court emphasized that federal habeas courts are prohibited from reexamining state-court determinations on state-law questions, as established in *Estelle v. McGuire*.
• The Court concluded that the "contingent features" of the case—such as the jury's specific inquiry or the centrality of the confessions—could not transform a judge's suppression analysis into a mandatory jury instruction under federal law.