Opinion of the Court
Contrary to the dissent, post, at 3, it makes no difference that Lynch did not alter federal law. While Arizona Supreme Court decisions applying Rule 32.1(g) to federal decisions such as Ring and Padilla have understandably noted the effect those decisions had on both federal and state law, the analytic focus of Arizona courts has always been on the impact to Arizona law. See supra, at 9–10; see also Towery, 204 Ariz., at 390, 64 P. 3d, at 832 (Ring “imposes a new burden on the state. Thus we conclude that Ring [satisfies Rule 32.1(g)]”). That focus is unsurprising given that Rule 32.1(g) is a state procedural rule governing the availability of state postconviction relief in state court.
The State next objects that a decision against it would forestall Arizona’s ability to “flesh out” its Rule 32.1(g) jurisprudence in new contexts. Tr. of Oral Arg. 40. That is incorrect. The Arizona Supreme Court is free to extend its prior Rule 32.1(g) jurisprudence, including by applying the Rule to new situations as they arise. What the Arizona Supreme Court cannot do is foreclose federal review by adopting a “ ‘novel and unforeseeable’ ” approach to Rule 32.1(g) that lacks “ ‘fair or substantial support in prior state law.’ ” Walker, 562 U. S., at 320 (quoting 16B Wright & Miller §4026, at 386).
The dissent argues that this case did present a new context because the Arizona Supreme Court had never before applied Rule 32.1(g) to a summary reversal. There was no reason, however, to treat this case any differently than past cases. Whereas the Arizona Supreme Court had previously looked to the effect of an intervening federal or state decision on Arizona law, supra, at 9–10, here it focused exclusively on whether there had been a change in federal law. The court thus disregarded that Lynch overruled “previously binding case law” in Arizona, the “archetype” of a significant change in the law. Shrum, 220 Ariz., at 118, 203
