I concur in the result and analysis of the majority opinion, but write separately to discuss a provocative argument of the Attorney General, one that, however, I believe must be accepted, if at all, by the United States Supreme Court in the first instance. The argument is based primarily on the concurring opinion of Justice Powell in Kimmelman v. Morrison (1986) All U.S. 365, 391-398 [91 L.Ed.2d 305, 329-334, 106 S.Ct. 2574] (Kimmelman).
*923The court today sets aside the judgment because defense counsel failed to make a meritorious objection to the admission of a tape recording of a conversation among petitioner and his partners in crime. During the course of that conversation, petitioner made a number of incriminating statements. The court finds prejudice, i.e., a reasonable probability that, absent the tape recording, there would have been a result more favorable to petitioner. As both the high court and this court have repeatedly stated, “A reasonable probability is a probability sufficient to undermine confidence in the outcome.” (Strickland v. Washington (1984) 466 U.S. 668, 694 [80 L.Ed.2d 674, 698, 104 S.Ct. 2052] [Strickland]; see In re Marquez (1992) 1 Cal.4th 584, 603 [3 Cal.Rptr.2d 121, 822 P.2d 435].)
No one has suggested that the tape recording of petitioner’s own words was anything but highly reliable, credible evidence. Its admission enhanced, it did not diminish, the ability of the jury to accurately determine the facts. The question is thus whether admission of such reliable evidence can ever establish prejudice under the Strickland standard, that is, whether our confidence in the outcome is undermined by the knowledge that the jury heard petitioner speak on tape. Justice Powell, joined by Chief Justice Burger and then-Justice Rehnquist, explored this question in Kimmelman, supra, All U.S. at pages 391-398 [91 L.Ed.2d at pages 329-334].
In that case, the majority held that a federal habeas corpus petition lies to challenge the effectiveness of defense counsel in failing to move to suppress evidence despite the general holding of Stone v. Powell (1976) 428 U.S. 465 [49 L.Ed.2d 1067, 96 S.Ct. 3037] that Fourth Amendment claims may not be brought on federal habeas corpus. Justice Powell concurred,, but also discussed the “more difficult question . . . whether the admission of illegally seized but reliable evidence can ever constitute ‘prejudice’ under Strickland.” (Kimmelman, supra, All U.S. at p. 391 [91 L.Ed.2d at p. 330] (conc. opn. of Powell, J.).) Justice Powell did not decide the question because it was never raised by the parties or discussed by the lower courts in the case, but he doubted that the erroneous admission of reliable evidence could ever be deemed prejudicial in the context of ineffective assistance of counsel claims.
Justice Powell noted that Strickland makes clear “the right to effective assistance of counsel is personal to the defendant, and is explicitly tied to the defendant’s right to a fundamentally fair trial—a trial in which the determination of guilt or innocence is ‘just’ and ‘reliable.’ ” (Kimmelman, supra, All U.S. at pp. 392-393 [91 L.Ed.2d at p. 331] (conc. opn. of Powell, J.).) He then argued that “the admission of illegally seized but reliable evidence does not lead to an unjust or fundamentally unfair verdict. . . . Indeed, it has *924long been clear that exclusion of illegally seized but wholly reliable evidence renders verdicts less fair and just, because it ‘deflects the truthfinding process and often frees the guilty.’ [Citations.] . . . Thus, the harm suffered by respondent in this case is not the denial of a fair and reliable adjudication of his guilt, but rather the absence of a windfall. [Fn. omitted.] Because the fundamental fairness of the trial is not affected, our reasoning in Strickland strongly suggests that such harm does not amount to prejudicial ineffective assistance of counsel under the Sixth Amendment.” (Id. at p. 396 [91 L.Ed.2d at p. 333], italics in original.)
Justice Powell quoted prior high court cases as “emphasizing]” that the “ ‘ ‘.‘very premise of our adversary system of criminal justice is that partisan advocacy on both sides of a case will best promote the ultimate objective that the guilty be convicted and the innocent go free.” ’ ” (Kimmelman, supra, All U.S. at p. 396 [91 L.Ed.2d at p. 333] (conc. opn. of Powell, J.), italics added by Justice Powell.) He argued that it would “shake” the right to effective assistance of counsel “loose from its constitutional moorings to hold that the Sixth Amendment protects criminal defendants against errors that merely deny those defendants a windfall. In this case, for example, the bedsheet [the evidence challenged in the case] may have provided critical evidence of respondent’s guilt, evidence whose relevance and reliability cannot seriously be questioned. The admission of the bedsheet thus harmed respondent only in the sense that it .helped the factfinder make a well-informed determination of respondent’s guilt or innocence. In my view, nothing in Strickland compels us to conclude that such an ‘injury’ establishes prejudice for purposes of respondent’s ineffective assistance claim.” (Id. at p. 397 [91 L.Ed.2d at pp. 333-334].)
Assuming there is not also some other basis upon which the judgment should be set aside, these words apply equally to this case. Petitioner has been prejudiced only in the sense that he did not have the windfall of keeping from the jury his own voluntarily spoken admissions. Nevertheless, like Justice Powell, although for a different reason, I feel constrained from accepting this argument. A holding that prejudice has not been shown for these reasons would effectively render meaningless the majority opinion in Kimmelman, supra, All U.S. 365, and would run counter to broad language found in that opinion. (Id. at pp. 379-380 [91 L.Ed.2d at pp. 321-323].) Any such holding should therefore first be made by the high court. Although that court recently cited Justice Powell’s concurring opinion in Kimmelman with apparent approval (Lockhart v. Fretwell (1993)_U.S._,_[122 L.Ed.2d 180, 191, 113 S.Ct. 838, 844]), it has not yet taken that step. I therefore concur.
I do so with some reluctance, however. To the extent the doctrine of ineffective assistance of counsel is intended to enhance the factual reliability *925of the determination of guilt or innocence, the outcome of this case does not do so. The tape recording of petitioner’s own words made the verdict more, not less, factually reliable. Any verdict by a jury at retrial without benefit of that recording will be, although possibly more favorable to petitioner, inherently less reliable than the one we set aside today.