Application of no-conduct credit provisions of amended Penal Code section 2933.6 to a prisoner whose commitment offense predates the amendment violates the ex post facto clause. In 2003, appellant pled guilty to robbery, gun use, and participation in a street gang, and was sentenced to prison. In 2009 he was validated as a “prison-gang associate” and sent to the Security Housing Unit (SHU) at Corcoran. At that time, section 2933.6 allowed prison-gang inmates in the SHU to earn restricted conduct credits. On January 25, 2010, section 2933.6 was amended to eliminate such credits. The amended provision was applied to appellant, which extended his release date. After exhausting his administrative remedies to challenge the reduction in his credits, appellant filed a petition for writ of habeas corpus in the trial court that included an ex post facto claim. Regarding the ex post facto claim, the court found appellant had not sought review in the proper forum. The Court of Appeal and State Supreme Court denied relief. After the federal district court denied relief, appellant appealed. Held: Reversed. A state may not pass any law that is retrospective and which disadvantages the offender by altering the definition of criminal conduct or increasing the punishment for the crime (U.S. Const., art. I, § 10, cl. 1). After section 2933.6 was amended in 2010, prison gang associates in the SHU no longer earn any credits, regardless of their conduct. A prisoner’s eligibility for early release by means of earning conduct credits is part of his underlying sentence, so changing his ability to earn credits changes the legal consequences of his underlying criminal conduct. As a result, section 2933.6 violates the prohibition against ex post facto laws when it is applied to prisoners whose underlying criminal conduct predates the statute’s enactment.

Because the superior court denied appellant’s petition on procedural grounds, no deference is given to that court’s decision under AEPDA. AEDPA bars a federal court from granting a writ petition with respect to any claim that was decided on the merits in the state court unless it involved an unreasonable application of clearly established federal law as determined by the U.S. Supreme Court. When the last reasoned state-court decision rejects a federal claim on procedural grounds, there is no presumption that any subsequent summary denial decided the claim on the merits. Here, the superior court denied appellant’s claim based on improper venue, not on the merits, so no AEDPA deference is due. Further, the state did not assert a state procedural ground in defense to appellant’s petition, so any such claim is waived.