In the United States ex rel. Jennings v. Ragen, Warden case of 1958, petitioner Jennings was convicted for murder in an Illinois state court and sentenced to life imprisonment. He sought a writ of habeas corpus from federal courts arguing that his constitutional rights were violated during his trial because he was not allowed to make a closing argument before the jury retired for deliberation. The District Court dismissed his petition without hearing evidence on whether this right existed under Illinois law at the time of conviction or if it had been waived by failure to object at trial. The Supreme Court held that dismissal without such evidentiary hearing was erroneous as these questions could not be resolved merely based on allegations and denials in pleadings; they required factual determination after appropriate hearings. Therefore, the judgment dismissing petitioner's application for writ of habeas corpus was reversed and remanded back to district court for further proceedings consistent with its opinion.

In the dissenting opinion for United States ex rel. Jennings v. Ragen, Warden, Justice Harlan argued that the majority's decision to dismiss Jennings' petition was premature and potentially unjust. He contended that while it may be true that Illinois courts could provide a sufficient remedy for Jennings' claims of constitutional violations in his trial and sentencing, this had not yet been definitively established at the time of dismissal. Therefore, he believed it would have been more appropriate to hold off on dismissing the case until there was clear evidence showing whether or not Illinois courts were able or willing to address these issues adequately. By failing to do so, Justice Harlan feared that they might inadvertently deny Jennings any opportunity for legal redress if it later turned out that state remedies were insufficient or unavailable.