In Walker v. Wainwright, the petitioner, a Florida state prisoner serving two concurrent life sentences for first-degree murder and robbery convictions, sought federal habeas corpus relief on the grounds that his constitutional rights were violated during his trial. He alleged that he was denied effective assistance of counsel because his attorney failed to object to certain evidence introduced at trial and did not adequately cross-examine witnesses or present a defense. The District Court dismissed the petition without an evidentiary hearing and this decision was affirmed by the Court of Appeals. However, upon reaching the Supreme Court in 1967, it was held that if facts are in dispute regarding whether or not there has been denial of constitutional rights such as effective legal representation then an evidentiary hearing must be conducted to resolve these issues. Therefore, it remanded (sent back) Walker's case for further proceedings consistent with its opinion - essentially instructing lower courts to conduct hearings when claims about ineffective legal counsel are made.

In the dissenting opinion for Walker v. Wainwright, Justice Douglas argued that the petitioner's constitutional rights were violated due to his lack of counsel during a critical stage in his trial process. The petitioner was denied an attorney when he requested one at a lineup before indictment, which is considered as a crucial part of proceedings where legal aid is necessary. He further noted that this denial could have influenced the outcome of the case since identification evidence obtained from such lineups can be highly persuasive to juries and may lead to wrongful convictions if not properly scrutinized by defense attorneys. Therefore, according to Justice Douglas' view, denying counsel at this point constitutes a violation of Sixth Amendment rights and undermines fair trial principles.