Ninth Circuit’s decision granting habeas relief reversed because AEDPA prohibits federal courts of appeal from relying on their own precedent to conclude that a particular constitutional principle is “clearly established.” During Smith’s first degree murder trial, the prosecutor argued Smith personally dealt the blow that killed his wife, who had threatened to divorce him. Smith’s defense was that he was not physically capable of inflicting the injury. Before closing argument, the trial court granted the prosecutor’s request to instruct the jury on aider and abettor liability. During the prosecutor’s closing, he argued that the jury could convict Smith of first degree murder under an aider and abettor theory even if it concluded that Smith was incapable of delivering the blow. The jury convicted Smith, but did not specify what theory it relied on. Smith appealed, arguing that he did not receive adequate notice of the possibility of conviction on an aider and abetter theory. The California Court of Appeal affirmed, reasoning that there is no requirement that a defendant be given advance notice of the particular theory of murder the prosecution intends to rely on. In federal habeas proceedings, the Ninth Circuit concluded that Smith’s Sixth Amendment and due process right to notice had been violated, citing its own precedent, Sheppard v. Rees (9th Cir. 1989) 909 F.2d 1234. The People sought review in the U.S. Supreme Court. Held: Reversed. AEDPA permits a federal court to grant a state prisoner habeas relief when a state court’s decision is “contrary to, or involved an unreasonable application of, clearly established federal law, as determined by the Supreme Court of the United States.” (28 U.S.C. § 2254 (d)(1).) Although the Ninth Circuit’s opinion in Sheppard found a due process notice violation on similar facts, no Supreme Court cases had done so. Thus, the California Court of Appeal’s decision finding no due process notice violation could not be an unreasonable application of clearly established Supreme Court precedent.