The exception to the procedural default rule laid out in Martinez v. Ryan applies where a state’s procedural rules effectively prevent a defendant from raising ineffective assistance of counsel (IAC) claims on direct appeal. Trevino was convicted of murder and sentenced to death by a Texas jury in 1997. His attorneys appointed for the direct appeal and state habeas proceedings did not raise IAC of trial counsel in failing to investigate and present mitigating evidence. After this IAC claim was raised for the first time in federal habeas proceedings, the state court held that Trevino procedurally defaulted the claim because he failed to raise it during the initial state collateral review proceedings. The federal district court then denied the IAC claim, concluding that an independent state ground (the default) barred the federal court from considering it. The Fifth Circuit affirmed. Held: Reversed. The “cause” exception to the procedural default rule outlined in Martinez v. Ryan (2012) 566 U.S. 1 applies to Texas’ criminal conviction review system. In Martinez, the court examined Arizona’s criminal conviction review system, which mandated that IAC claims be raised in a separate postconviction challenge (in which there is no constitutional right to an attorney), and not on direct appeal (in which the defendant is entitled to counsel). It found that federal courts may review procedurally defaulted IAC claims in Arizona cases if the defendant had no attorney in the separate postconviction proceeding or if his/her attorney was ineffective. “By deliberately choosing to move trial [IAC] claims outside the direct-appeal process, where counsel is constitutionally guaranteed, the state significantly diminishes prisoners’ ability to file such claims.” In the present case, while Texas seemingly allows IAC claims to be raised on direct appeal, its procedural framework makes it virtually impossible to do so. “What the Arizona law prohibited by explicit terms, Texas law precludes as a matter of course.” Because there is no significant difference between Arizona and Texas law, the holding of Martinez applies.