Justice Stewart
delivered the opinion of the Court.
These cases, consolidated for argument and decision in the Court of Appeals and in this Court, present the question whether a state criminal trial court is constitutionally compelled to conduct a hearing outside the presence of the jury whenever a defendant contends that a witness’ identification of him was arrived at improperly.
I
A
John Watkins, the petitioner in No. 79-5949, was convicted in a Kentucky court of attempting to rob a Louisville liquor store. On the night of January 11, 1975, four men entered the store, one of whom asked for a pack of cigarettes. Walter Smith, an employee of the store, turned around to get the cigarettes, and one of the men said “[t]his is a hold-up.” Donald Goeing, a part owner of the store, had been stocking a soft-drink cooler, and when he heard those words, he turned towards the robbers. The man who had spoken thereupon fired two shots at him, one striking him in his arm, the other in the region of his heart. The four men then fled.
That night Smith and Goeing described the gunman to the police. Two days later, the police in the presence of Smith conducted a lineup consisting of three men, one of whom was Watkins. Smith identified Watkins as the gunman. That same day, the police took Watkins to Goeing’s hospital bed, and Goeing identified Watkins as the man who had shot him. Watkins was then charged with first-degree robbery and first-degree assault.
At the subsequent trial of Watkins, the prosecution called Smith and Goeing as witnesses. They both identified Watkins as Goeing’s assailant but were not asked by the prosecution about the lineup or the showup. Watkins’ counsel, however, cross-examined both men at some length about both the lineup and showup. The prosecution then called a police officer. He testified that he had taken Watkins to be identified at the hospital because “at that time there was some question as to whether or not Mr. Goeing was going to survive the incident.” Watkins’ counsel cross-examined the officer about both the showup and the lineup and through him introduced pictures of the lineup. For the defense, Watkins’ counsel called two witnesses who said that they had been in a pool hall with Watkins at the time of the robbery and another witness who said he had been in the liquor store at the time of the robbery and had not seen Watkins. Finally, Watkins himself testified to his innocence.
On appeal, as he had at trial, counsel for Watkins argued that the trial court had a constitutional obligation to conduct a hearing outside the presence of the jury to determine whether the identification evidence was admissible. The Supreme Court of Kentucky rejected that argument. Relying on its decision in Ray v. Commonwealth, 550 S. W. 2d 482, 483 (1977), the court said “ ‘[ajlthough we are of the opinion that the holding of such a hearing prior to the introduction of this testimony would have been the preferred course to follow, we are not persuaded the failure to have done so requires reversal of appellant’s conviction.’ ” Watkins v. Commonwealth, 565 S. W. 2d 630, 631 (1978). The court found that the identification procedures “fail[edj to raise any impermissible suggestiveness” and that Watkins “was in no way prejudiced.” Ibid.
Watkins then unsuccessfully sought a writ of habeas corpus in the United States District Court for the Western District of Kentucky. That court held that, “although pretrial suppression hearings are preferable, the failure to hold them does not require the reversal of a conviction.” The court also found that admission of neither the lineup nor the showup evidence at the state trial had violated constitutional standards.
The Court of Appeals for the Sixth Circuit affirmed the District Court’s judgment and, like the District Court, ruled that a hearing on the admissibility of identification evidence need not be held outside the presence of the jury. Turning to the evidence itself, the court cited Stovall v. Denno, 388 U. S. 293, as authority for holding that “[g]iven the seriousness of the wounds to Donald Goeing, a showup was necessary in this case.” Summitt v. Bordenkircher, 608 F. 2d 247, 252. The federal appellate court also held that the lineup evidence had been constitutionally admissible at the state trial.
B
James Summitt, the petitioner in No. 79-5951, was convicted in a Kentucky court of rape. Late on the night of July 20, 1974, the prosecutrix was forced into a car occupied by two men, driven to an isolated location, raped by one of the men, and then returned to her own car. The next day she reported the crime to the police, described the rapist, and looked through 12 volumes of photographs from police files, without identifying the man who had raped her. Two days later she was taken to another police station, where she examined more pictures. A police officer testified at the subsequent trial of Summitt that “after a short time she pointed to the defendant’s picture and said: ‘This is the man that raped me. There’s no doubt about it, this is Jimbo, the man that raped me.’ ” In addition to the officer, the prosecutrix and her stepfather as witnesses for the prosecution described the pros-ecutrix’s examination of the police photographs, and the pros-ecutrix testified that Summitt was the man who had raped her. There was extensive cross-examination.
The Supreme Court of Kentucky found “no error in the trial court’s refusal to conduct a suppression hearing and no semblance of impermissible suggestiveness in the identification procedure.” Summitt v. Commonwealth, 550 S. W. 2d 548, 550 (1977). Summitt then sought a writ of habeas corpus in the United States District Court for the Western District of Kentucky, but that court found no constitutional error. The Court of Appeals, as in the consolidated Watkins case, affirmed the judgment of the District Court, 608 F. 2d 247.
We granted certiorari to consider the constitutional claim asserted by both petitioners throughout their state and federal court proceedings. Sub nom. Watkins v. Bordenkircher and Summitt v. Bordenkircher, 445 U. S. 926.
II
The issue before us is not, of course, whether a trial court acts prudently in holding a hearing out of the presence of the jury to determine the admissibility of identification evidence. The prudence of such a hearing has been emphasized by many decisions in the Courts of Appeals, most of which have in various ways admonished trial courts to use that procedure. The issue here, rather, is whether such a hearing is required by the Due Process Clause of the Fourteenth Amendment.
In urging an affirmative answer, the petitioners first cite cases holding that a defendant has a right to the presence of his counsel at a postindictment lineup, e. g., United States v. Wade, 388 U. S. 218, and that an identification procedure, in the absence of a lineup, may be so defective as to deprive a defendant of due process of law, e. g., Stovall v. Denno, 388 U. S. 293. The petitioners then analogize their cases to Jackson v. Denno, 378 U. S. 368, in which this Court enunciated a defendant's right “to have a fair hearing and a reliable determination on the issue of voluntariness,” id., at 377, and in which the Court declared unconstitutional a New York procedure which gave the jury what was in practice unre-viewable discretion to decide whether a confession was or was not voluntary.
The petitioners contend that Jackson v. Denno established a per se due process right to a hearing outside the presence of the jury whenever a question of the voluntariness of a confession is raised. If such a hearing is required where the voluntariness of a confession is at issue, it follows, the petitioners argue, that a similar hearing must also be required where the propriety of identification procedures has been questioned.
Even if it be assumed that Jackson v. Denno did establish the per se rule asserted, the petitioners’ argument must fail, because Jackson v. Denno is not analogous to the cases now before us. The Court in Jackson did reject the usual presumption that a jury can be relied upon to determine issues according to the trial judge’s instructions, but the Court did so because of the peculiar problems the issue of the volun-tariness of a confession presents. The Court pointed out that, while an involuntary confession is inadmissible in part because such a confession is likely to be unreliable, it is also inadmissible even if it is true, because of the “ 'strongly felt attitude of our society that important human' values are sacrificed where an agency of the government, in the course of securing a conviction, wrings a confession out of an accused against his will.’ ” Id., at 385, quoting Blackburn v. Alabama, 361 U. S. 199, 206-207. The Court concluded in Jackson that a jury “may find it difficult to understand the policy forbidding reliance upon a coerced, but true, confession .... Objective consideration of the conflicting evidence concerning the circumstances of the confession becomes difficult and the [jury’s] implicit findings become suspect.” Id., at 382.
Where identification evidence is at issue, however, no such special considerations justify a departure from the presumption that juries will follow instructions. It is the reliability of identification evidence that primarily determines its admissibility, Manson v. Brathwaite, 432 U. S. 98, 113-114; United States ex rel. Kirby v. Sturges, 510 F. 2d 397, 402-404 (CA7 1975) (Stevens, J.). And the proper evaluation of evidence under the instructions of the trial judge is the very task our system must assume juries can perform. Indeed, as the cases before us demonstrate, the only duty of a jury in cases in which identification evidence has been admitted will often be to assess the reliability of that evidence. Thus the Court’s opinion in Manson v. Brathwaite approvingly quoted Judge Leventhal’s statement that,
“ ‘[w]hile identification testimony is significant evidence, such testimony is still only evidence, and, unlike the presence of counsel, is not a factor that goes to the very heart — the ‘integrity’' — of the adversary process.
“ ‘Counsel can both cross-examine the identification witnesses and argue in summation as to factors causing doubts as to the accuracy of the identification — including reference to both any suggestibility in the identification procedure and any countervailing testimony such as alibi.’ ” 432 U. S., at 114, n. 14, quoting Clemons v. United States, 133 U. S. App. D. C. 27, 48, 408 F. 2d 1230, 1251 (1968) (concurring opinion) (footnote omitted).
The petitioners argue, however, that cross-examination is inadequate in cases such as these. They assert that the presence of the jury deterred their lawyers from cross-examining the witnesses vigorously and fully as to the possible improprieties of the pretrial identifications in these cases. The petitioners point to no specific instances in the trial when their counsel were thus deterred, and the record reveals that the cross-examination on the identity issues was, if not always effective, both active and extended. Nonetheless, the petitioners rely on a passage from United States v. Wade, supra, which referred to
“the predicament in which Wade’s counsel found himself — realizing that possible unfairness at the lineup may be the sole means of attack upon the unequivocal courtroom identification, and having to probe in the dark in an attempt to discover and reveal unfairness, while bolstering the government witness’ courtroom identification by bringing out and dwelling upon his prior identification.” 388 U. S., at 240-241.
The petitioners, however, attribute undue significance to this passage. The “predicament” described in Wade was no more than part of the Court’s demonstration that, if identification stemming from an improperly conducted lineup was to be excluded, a courtroom identification based on such a lineup logically had to be excluded as well.
A “predicament,” if one chooses to call it that, is always presented when a lawyer decides on cross-examination to ask a question that may produce an answer unfavorable to his client. Yet, under our adversary system of justice, cross-examination has always been considered a most effective way to ascertain truth. We decline in these cases to hold that the Due Process Clause of the Fourteenth Amendment inevitably requires the abandonment of the time-honored process of cross-examination as the device best suited to determine the trustworthiness of testimonial evidence.
A judicial determination outside the presence of the jury of the admissibility of identification evidence may often be advisable. In some circumstances, not presented here, such a determination may be constitutionally necessary. But it does not follow that the Constitution requires a per se rule compelling such a procedure in every case.
Accordingly, the judgments are
Affirmed.
The opinion of the District Court is unreported.
E. g., United States v. Mitchell, 540 F. 2d 1163 (CA3 1976); United States v. Cranson, 453 F. 2d 123 (CA4 1971); Haskins v. United States, 433 F. 2d 836 (CA10 1970); United States v. Ranciglio, 429 F. 2d 228 (CA8 1970); United States v. Allison, 414 F. 2d 407 (CA9 1969); United States v. Broadhead, 413 F. 2d 1351 (CA7 1969); Clemons v. United States, 133 U. S. App. D. C. 27, 408 F. 2d 1230 (1968) (en banc). The Court of Appeals for the Fifth Circuit has left the matter to the discretion of the district courts. United States v. Smith, 546 F. 2d 1275 (1977). At least two Federal Courts of Appeals have commended hearings outside the presence of the jury to state courts, Nassar v. Vinzant, 519 F. 2d 798 (CA1 1975); United States ex rel. Phipps v. Follette, 428 F. 2d 912 (CA2 1970), and at least one has held that due process may in some circumstances require a hearing outside the presence of a jury to decide the admissibility of identification evidence. United States ex rel. Fisher v. Driber, 546 F. 2d 18 (CA3 1976).
See Pinto v. Pierce, 389 U. S. 31, 32:
“This Court has never ruled that all voluntariness hearings must be held outside the presence of the jury, regardless of the circumstances. . . . [Bjecause a disputed confession may be found involuntary and inadmissible by the judge, it would seem prudent to hold voluntariness hearings outside the presence of the jury. ... In this case, however, the confession was held voluntary and admitted as evidence suitable for consideration by the jury.”
As Professor Wigmore put it, “[cross-examination] is beyond any doubt the greatest legal engine ever invented for the discovery of truth.” 5 J. Wigmore, Evidence § 1367 (Chadbourn rev. 1974).
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