Warden v. Lee, 578 U.S. ___, 136 S. Ct. 1802 (May. 31, 2016)

The Ninth Circuit erred by concluding that the California “Dixon bar”--providing that a defendant procedurally defaults a claim raised for the first time on state collateral review if he could have raised it earlier on direct appeal—was inadequate to bar federal habeas review. Federal habeas courts generally refuse to hear claims defaulted in state court pursuant to an independent and adequate state procedural rule. State rules are “adequate” if they are firmly established and regularly followed. California’s Dixon bar meets this standard.