with whom The Chief Justice, Justice O’Connor, and Justice ScALiAjoin, dissenting.
To deprive the prosecution of probative evidence acquired in violation of the law may be a tolerable and necessary cost of the exclusionary rule. Implementation of the rule requires us to draw certain lines to effect its purpose of deterring unlawful conduct. But the line drawn by today’s opinion grants the defense side in a criminal case broad immunity to introduce whatever false testimony it can produce from the mouth of a friendly witness. Unless petitioner’s conviction is reversed, we are told, police would flout the Fourth Amendment, and as a result, the accused would be unable to offer any defense. This exaggerated view leads to a drastic remedy: The jury cannot learn that defense testimony is inconsistent with probative evidence of undoubted value. A more cautious course is available, one that retains Fourth Amendment protections and yet safeguards the truth-seeking function of the criminal trial.
Our precedents establish that the exclusionary rule does not apply where the interest in pursuing truth or other important values outweighs any deterrence of unlawful conduct that the rule might achieve. See, e. g., Illinois v. Krull, 480 U. S. 340, 347-348 (1987); United States v. Leon, 468 U. S. 897, 906-907 (1984); Stone v. Powell, 428 U. S. 465, 486-489 (1976); United States v. Calandra, 414 U. S. 338, 347-348 (1974). One instance is a defendant’s attempt to take advantage by presenting testimony in outright contradiction of ex-*323eluded facts, secure in the knowledge that the inconsistency will not be revealed to the jury. As we said over 35 years ago:
“It is one thing to say that the Government cannot make an affirmative use of evidence unlawfully obtained. It is quite another to say that the defendant can turn the illegal method by which evidence in the Government’s possession was obtained to his own advantage, and provide himself with a shield against contradiction of his untruths. Such an extension of the Weeks [v. United States, 232 U. S. 383 (1914),] doctrine would be a perversion of the Fourth Amendment.” Walder v. United States, 347 U. S. 62, 65 (1954).
Under this rationale, our consistent rule has been that a defendant’s testimony is subject to rebuttal by contradicting evidence that otherwise would be excluded. The principle applies to suppressed physical evidence, as in Walder itself and United States v. Havens, 446 U. S. 620 (1980), and to statements obtained in violation of the law, so long as the statements are voluntary and reliable, see Oregon v. Hass, 420 U. S. 714 (1975); Harris v. New York, 401 U. S. 222 (1971).
Petitioner argues that the rationale of these cases is confined to “impeachment” of testimony presented by the defendant himself because these cases involve only “impeachment by self-contradiction.” Brief for Petitioner 13. The theory, it seems, is that excluded evidence introduced in opposition to the defendant’s testimony impeaches by means of the contradiction itself; the substantive truth or falsity of the suppressed evidence is irrelevant. Our cases do not bear this reading. In Havens, the defendant was charged as an accomplice in the smuggling of narcotics. A codefendant hid the drugs in a T-shirt constructed with special pockets. The pockets were made of patches cut from another T-shirt found in the defendant’s luggage during an illegal search. When the defendant denied having possessed the T-shirts, the cut *324T-shirt, which had been excluded at the outset, was admitted as rebuttal evidence. We upheld its admission. See 446 U. S., at 623, 628. There was no “self-contradiction” involved, for the rebuttal of the defendant’s testimony could only have been based on the jury’s belief in the substantive truth of the fact that the altered T-shirt was used in the smuggling, and that it belonged to the defendant. The same was true in Walder, where we upheld the admission of illegally seized heroin from an unrelated investigation to impeach the defendant’s statement that he had never possessed the drug. In sum, our cases show that introduction of testimony contrary to excluded but reliable evidence subjects the testimony to rebuttal by that evidence.
I agree with the majority that the resolution of this case depends on a balance of values that informs our exclusionary rule jurisprudence. We weigh the “‘likelihood of. . . deterrence against the costs of withholding reliable information from the truth-seeking process.’” Ante, at 312, n. 1 (quoting Illinois v. Krull, supra, at 347). The majority adopts a sweeping rule that the testimony of witnesses other than the defendant may never be rebutted with excludable evidence. I cannot draw the line where the majority does.
The interest in protecting the truth-seeking function of the criminal trial is every bit as strong in this case as in our earlier cases that allowed rebuttal with evidence that was inadmissible as part of the prosecution’s case in chief. Here a witness who knew the accused well took the stand to testify about the accused’s personal appearance. The testimony could be expected to create real doubt in the minds of jurors concerning the eyewitness identifications by persons who did not know the accused. To deprive the jurors of knowledge that statements of the defendant himself revealed the witness’ testimony to be false would result in a decision by triers of fact who were not just kept in the dark as to excluded evidence, but positively misled. The potential for harm to the truth-seeking process resulting from the majority’s new rule *325in fact will be greater than if the defendant himself had testified. It is natural for jurors to be skeptical of self-serving testimony by the defendant. Testimony by a witness said to be independent has the greater potential to deceive. And if a defense witness can present false testimony with impunity, the jurors may find the rest of the prosecution’s case suspect, for ineffective and artificial cross-examination will be viewed as a real weakness in the state’s case. Jurors will assume that if the prosecution had any proof the statement was false, it would make the proof known. The majority does more than deprive the prosecution of evidence. The state must also suffer the introduction of false testimony and appear to bolster the falsehood by its own silence.
The majority’s fear that allowing the jury to know the whole truth will chill defendants from putting on any defense seems to me far too speculative to justify the rule here announced. No restriction on the defense results if rebuttal of testimony by witnesses other than the defendant is confined to the introduction of excludable evidence that is in direct contradiction of the testimony. If mere “tension with the tainted evidence,” ante, at 315, opened the door to introduction of all the evidence subject to suppression, then the majority’s fears might be justified. But in this context rebuttal can and should be confined to situations where there is direct conflict, which is to say where, within reason, the witness’ testimony and the excluded testimony cannot both be true.1
*326Also missing from the majority’s analysis is the almost certain knowledge that the testimony immunized from rebuttal is false. The majority’s apparent assumption that defense witnesses protected by today’s rule have only truthtelling in mind strikes me as far too sanguine to support acceptance of a rule that controls the hard reality of contested criminal trials. The majority expresses the common sense of the matter in saying that presentation of excluded evidence must sometimes be allowed because it “penalizes defendants for committing perjury.” Ante, at 314.
In some cases, of course, false testimony can result from faulty recollection. But the majority’s ironclad rule is one that applies regardless of the witness’ motives, and may be misused as a license to perjure. Even if the witness testifies in good faith, the defendant and his lawyer, who offer the testimony, know the facts. Indeed, it is difficult here to imagine the defense attorney’s reason for asking Henderson about petitioner’s hair color if he did not expect her to cast doubt on the eyewitness identification of petitioner by giving a description of petitioner’s hair color contrary to that contained in his own (suppressed) statement.
The suggestion that the threat of a perjury prosecution will provide sufficient deterrence to prevent false testimony, ante, *327at 314 (opinion of Brennan, J.); ante, at 320-321 (opinion of Stevens, J.), is not realistic. See generally Dunn v. United States, 442 U. S. 100, 108 (1979) (describing proof of perjury as “exceptionally difficult”). A heightened proof requirement applies in Illinois and other States, making perjury convictions difficult to sustain. See People v. Alkire, 321 Ill. 28, 151 N. E. 518 (1926); People v. Harrod, 140 Ill. App. 3d 96, 488 N. E. 2d 316 (1986). Where testimony presented on behalf of a friend or family member is involved, the threat that a future jury will convict the witness may be an idle one.
The damage to the truth-seeking process caused by the majority’s rule is certain to be great whether the testimony is perjured or merely false. In this case there can be little doubt of the falsity, since petitioner’s description of his own hair was at issue. And as a general matter the alternative to rebuttal is endorsement of judicial proceedings conducted in reliance on information known to be untrue. Suppressed evidence is likely to consist of either voluntary statements by the defendant himself or physical evidence. Both have a high degree of reliability, and testimony in direct conflict to such evidence most often will represent an attempt to place falsehoods before the jury.2
*328The suggestion that all this is so far beyond the control of the defendant that he will put on no defense is not supported. As to sympathetic witnesses, such as the family friend here, it should not be too hard to assure the witness does not volunteer testimony in contradiction of the facts. The defendant knows the content of the suppressed evidence. Even in cases- where the time for consultation is limited, the defense attorney can take care not to elicit contradicting testimony. And in the case of truly neutral witnesses, or witnesses hostile to the accused, it is hard to see the danger that they will present false testimony for the benefit of the defense.
The majority’s concerns may carry greater weight where contradicting testimony is elicited from a defense witness on cross-examination. In that situation there might be a concern that the prosecution would attempt to produce such testimony as the foundation to put excluded evidence before the jury. We have found that possibility insufficient to justify immunity for a defendant’s own false testimony on cross-examination. United States v. Havens, 446 U. S. 620 (1980). As to cross-examination of other witnesses, perhaps a different rule could be justified. Rather than wait for an appropriate case to consider this or similar measures, however, the majority opts for a wooden rule immunizing all defense testimony from rebuttal, without regard to knowledge that the testimony introduced at the behest of the defendant is false or perjured.
I also cannot agree that admission of excluded evidence on rebuttal would lead to the “disregard of . . . constitutional rights,” by law enforcement officers, ante, at 319, that the majority fears. This argument has been raised in our previous cases in this area of the law. See Havens, supra, at 633-634 (Brennan, J., dissenting); Hass, 420 U. S., at 725 (Brennan, J., dissenting); Harris, 401 U. S., at 232 (Brennan, J., dissenting). To date we have rejected it. Now the specter appears premised on an assumption that a single slip of the tongue by any defense witness will open the door to *329any suppressed evidence at the prosecutor’s disposal. If this were so, the majority’s concern that officers would be left with little to lose from conducting an illegal search would be understandable. And the argument might hold more force if, as the majority speculates, ante, at 319, police confront the temptation to seize evidence illegally “much if not most of the time” after gathering sufficient evidence to present proof of guilt beyond a reasonable doubt in the case in chief. Again, however, I disagree with the predictions.
It is unrealistic to say that the decision to make an illegal search turns on a precise calculation of the possibilities of rebuttal at some future trial. There is no reason to believe a police officer, unschooled in the law, will assess whether evidence already in his possession would suffice to survive a motion for acquittal following the case in chief. The officer may or may not even know the identity of the ultimate defendant.3 He certainly will not know anything about potential defense witnesses, much less what the content of their testimony might be. What he will know for certain is that evidence from an illegal search or arrest (which may well be crucial to securing a conviction) will be lost to the case in chief. Our earlier assessments of the marginal deterrent effect are applicable here. “Assuming that the exclusionary rule has a deterrent effect on proscribed police conduct, sufficient deterrence flows when the evidence in question is made un*330available to the prosecution in its case in chief.” Harris, supra, at 225.
In this case, the defense witness, one Jewel Henderson, testified that petitioner’s hair was black on the date of the offense. Her statement, perjured or not, should not have been offered to the jurors without giving them the opportunity to consider the unequivocal and contradicting description by the person whose own hair it was. I would allow the introduction of petitioner’s statement that his hair was red on the day of the shootings. The result is consistent with our line of cases from Walder to Havens and compelled by their reasoning.
The prosecution, it is true, did not limit itself to petitioner’s description of his hair color. It went beyond this to introduce petitioner’s statement that he went to the beauty shop to “change his appearance.” App. 11. The prosecutor used this statement to suggest that petitioner had a guilty mind and an intention to evade capture by disguise. This goes beyond what was necessary to rebut Henderson’s testimony and raises many of the concerns expressed in the majority opinion. Nonetheless, there was overwhelming evidence of petitioner’s guilt in this case, including the testimony of five eyewitnesses. In view of these circumstances, I agree with the Illinois Supreme Court that any error as to the additional statements or the prosecutor’s argument had no effect on petitioner’s trial and may be considered harmless.
Where the jury is misled by false testimony, otherwise subject to flat contradiction by evidence illegally seized, the protection of the exclusionary rule is “‘perverted into a license to use perjury by way of a defense, free from the risk of confrontation with prior inconsistent utterances.’” Havens, supra, at 626 (quoting Harris, supra, at 226). The perversion is the same where the perjury is by proxy. I would affirm the judgment of the Illinois Supreme Court.
Defining the proper scope of rebuttal is a task that trial judges can be expected to perform without difficulty, for this type of inquiry is a familiar one. In a different context, for example, Federal Rule of Evidence 801(d) (1) provides that a prior statement under oath is not hearsay if “the statement is . . . inconsistent with the declarant’s testimony.” Likewise, Rule 613(b) contemplates the admission of extrinsic evidence of a “prior inconsistent statement.” Trial judges apply these and similar state rules every day, and general formulations of the principles involved are commonplace. For example, the relevant question has been described as whether two statements “cannot at the same time be true .... Thus, it is not a mere difference of statement that suffices; nor yet is an absolute oppositeness *326essential; it is an inconsistency that is required.” 3A J. Wigmore, Evidence § 1040 (J. Chadbourn rev. 1970).
The trial court’s handling of the rebuttal in this case provides an illustration. There is no suggestion that the trial court considered witness Jewel Henderson’s testimony about petitioner’s hair color to be a basis for admitting petitioner’s other statements about the shootings. Henderson also testified that she was with petitioner at his home on the night of the shooting, and that petitioner had arrived there between 10 and 11 p.m., but that she could not be specific about the time. The State sought to rebut this testimony with petitioner’s suppressed statements about the shooting, contending that Henderson’s testimony established an alibi for the shooting, which occurred around 11 p.m. The court concluded that no alibi was established and refused to allow introduction of the suppressed statements on rebuttal. The trial court thus refused to introduce excluded evidence on the basis of mere tension with the witness’ statement.
Justice Stevens takes exception to the “assumption” that the police officer’s recollection of James’ statement about his hair was reliable. Ante, at 321. But one need hardly be credulous to so describe the officer’s testimony. James, it must be remembered, said his hair was previously red and straight just after he emerged from the dryer with curlers still in his hair. Moreover, in cases involving the suppression of physical evidence, which the majority’s rule must also govern, the reliability of the suppressed evidence itself will not be in question since the evidence is not testimonial. In any event, the issue here is not credibility. Perhaps a jury in this case would also find reasons to be skeptical of the rebuttal testimony. My point is that the factfinder should be given the chance to do so. This will not happen under the majority’s approach, by which, as I have said, the verdict will be delivered by jurors who have been misled.
In this case, contrary to the impression conveyed by the majority, ante, at 319, n. 8, the arresting officers knew almost nothing of the state of a future prosecution ease. The officers did know there were several eyewitnesses to the shooting. But these eyewitnesses had made no identification of any suspect. The officers did not know petitioner’s real name or his true appearance, but had sought him out at the beauty parlor on an anonymous tip. They could not know what physical evidence, such as the murder weapon, they might find on petitioner, or might lose to the case in chief as a result of illegal conduct. The suggestion that the officers’ calculated assessment of a future trial allowed them to ignore the exclusionary rule finds no support in the record and, in fact, is pure speculation.