In collateral state court proceedings, respondent, a Cuban immigrant with little education and almost no knowledge of English, alleged, inter alia, that his plea of nolo contendere to first-degree manslaughter had not been knowing and intelligent, and therefore was invalid because his court-appointed translator had not translated accurately and completely for him the mens rea element of the crime in question. The state court dismissed the petition after a hearing, the Oregon Court of Appeals affirmed, the State Supreme Court denied review, and the Federal District Court denied respondent habeas corpus relief. However, the Court of Appeals held that he was entitled to a federal evidentiary hearing on the question whether the mens rea element of the crime was properly explained to him, since the record disclosed that the material facts concerning the translation were not adequately developed at the state court hearing, see Townsend v. Sain, 372 U.S. 293, 313, and since postconviction counsels negligent failure to develop those facts did not constitute