In Crane v. Kentucky (1986) 476 U.S. 683, the appellant sought to introduce testimony concerning the length of his interrogation and the manner in which it was conducted in an effort to demonstrate the confession was not reliable. ( Id. at p. 684.) The trial court excluded the testimony on the ground that it was relevant only to the issue of voluntariness, which was not before the jury. The Supreme Court disagreed, drawing a clear distinction between the voluntariness of a confession, a legal issue, and the separate question of its reliability, a factual question. The court held that appellant was deprived of his due process right to a fair opportunity to present his defense based on the trial court's exclusion of evidence challenging the confession's reliability. ( Id. at p. 691.) In Crane v. Kentucky, after the trial court refused to suppress an allegedly involuntary confession, the defendant tried to introduce the same evidence in order to persuade the jury his confession was unreliable. The trial court concluded the evidence was inadmissible because it pertained solely to voluntariness. Crane ruled: "The holding below rests on the apparent assumption that evidence bearing on the voluntariness of a confession and evidence bearing on its credibility fall in conceptually distinct and mutually exclusive categories. Once a confession has been found voluntary, the Supreme Court of Kentucky believed, the evidence that supported that finding may not be presented to the jury for any other purpose. This analysis finds no support in our cases, is premised on a misconception about the role of confessions in a criminal trial, and, under the circumstances of this case, contributed to an evidentiary ruling that deprived petitioner of his fundamental constitutional right to a fair opportunity to present a defense." (Crane v. Kentucky, supra, 476 U.S. at p. 687.) Crane reasoned "evidence about the manner in which a confession was secured will often be germane to its probative weight, a matter that is exclusively for the jury to assess." (Crane v. Kentucky, supra, 476 U.S. at p. 688.) "The circumstances surrounding the taking of a confession can be highly relevant to two separate inquiries, one legal and one factual. The manner in which a statement was extracted is, of course, relevant to the purely legal question of its voluntariness, a question most, but not all, States assign to the trial judge alone to resolve. But the physical and psychological environment that yielded the confession can also be of substantial relevance to the ultimate factual issue of the defendant's guilt or innocence. Confessions, even those that have been found to be voluntary, are not conclusive of guilt. And, as with any other part of the prosecutor's case, a confession may be shown to be 'insufficiently corroborated or otherwise . . . unworthy of belief.' Indeed, stripped of the power to describe to the jury the circumstances that prompted his confession, the defendant is effectively disabled from answering the one question every rational juror needs answered: If the defendant is innocent, why did he previously admit his guilt" Accordingly, . . . a defendant's case may stand or fall on his ability to convince the jury that the manner in which the confession was obtained casts doubt on its credibility." (Id. at pp. 688-689.)The high court held that a defendant is entitled to introduce evidence regarding the circumstances of his confession even if the confession is voluntary. (Crane, at p. 689.) As the court explained, "the physical and psychological environment that yielded the confession can also be of substantial relevance to the ultimate factual issue of the defendant's guilt or innocence. Confessions, even those that have been found to be voluntary, are not conclusive of guilt." (Crane, at p. 689.) After the trial court found his confession voluntary, the defendant sought to present evidence regarding the circumstances in which the confession was obtained in order to suggest the jury should not find it worthy of belief. (Id. at p. 684.) The trial court, viewing the evidence as relevant only to the already determined question of voluntariness, ruled it inadmissible. (Ibid.) Crane reversed, finding the exclusion of "competent, reliable evidence bearing on the credibility of a confession when such evidence is central to the defendant's claim of innocence" deprived the defendant of his right to present his defense. (Id. at pp. 690-691.) In Crane v. Kentucky (1986) 476 U.S. 683, the trial court, after conducting an evidentiary hearing, denied a motion to suppress a confession of murder that the defendant claimed was coerced by improper police interrogation tactics. (Crane, supra, 476 U.S. at pp. 684-685.) Thereafter, during trial, the court precluded the defendant from presenting evidence concerning the circumstances surrounding the confession to attack its credibility; it concluded that such evidence was only relevant to the voluntariness of the defendant's confession, a matter the court had already decided. (Id. at pp. 685-686.) On appeal from the judgment of conviction, the Supreme Court reversed, concluding that the exclusion of evidence attacking the credibility of the confession prevented the defendant from having had a fair opportunity to present a defense. (Id. at pp. 690-691.) It held that "the circumstances surrounding the taking of a confession can be highly relevant to two separate inquiries, one legal and one factual. The manner in which a statement was extracted is, of course, relevant to the purely legal question of its voluntariness, . . . But the physical and psychological environment that yielded the confession can also be of substantial relevance to the ultimate factual issue of the defendant's guilt or innocence. Confessions, even those that have been found to be voluntary, are not conclusive of guilt. And, as with any other part of the prosecutor's case, a confession may be shown to be 'insufficiently corroborated or otherwise . . . unworthy of belief.' Indeed, stripped of the power to describe to the jury the circumstances that prompted his confession, the defendant is effectively disabled from answering the one question every rational juror needs answered: If the defendant is innocent, why did he previously admit his guilt? Accordingly, regardless of whether the defendant marshaled the same evidence earlier in support of an unsuccessful motion to suppress, and entirely independent of any question of voluntariness, a defendant's case may stand or fall on his ability to convince the jury that the manner in which the confession was obtained casts doubt on its credibility." (Id. at pp. 688-689.)