David Martinez Ramirez and Barry Jones were convicted of capital crimes in Arizona and later sought federal habeas relief based on alleged ineffective assistance at trial. They argued that postconviction counsel’s failure to develop the record should not prevent federal evidentiary hearings because their states required ineffective-assistance claims to be raised in postconviction proceedings. The Supreme Court held that the equitable exception recognized in Martinez and Trevino does not permit a federal court to bypass the statutory limits on evidentiary development in federal habeas proceedings. When a petitioner failed to develop the factual basis of a claim in state court, the statute restricts a federal hearing, subject to narrow exceptions that were not satisfied here. The Court also rejected a separate request for relief based on postconviction counsel’s ineffectiveness. Justice Sotomayor dissented, arguing that the decision undermined the constitutional protection recognized in Martinez and Trevino for prisoners whose trial-ineffectiveness claims could be raised only in collateral proceedings.