I concur in the judgment insofar as it affirms the judgment of the trial court as to guilt and death-eligibility (except as to the conviction for assault with a deadly weapon). With the exception noted, I find no reversible error affecting the verdicts the jury returned or the findings it made.
I dissent, however, from the judgment insofar as it vacates the judgment of the trial court as to penalty. As I shall explain, at the penalty phase the jury was exposed to a “crime” of which defendant had been prosecuted and acquitted —a “crime” that was inadmissible as a matter of law. It is hard to determine with certainty why the prosecutor, who urged the jurors to “follow the law,” himself violated the law by introducing and arguing evidence of the “crime”; or why the court allowed him to do so and even instructed on the matter; or why defense counsel did nothing to keep the “crime” from the jury. But it is easy to see what flowed from the acts and omissions of prosecutor, court, and counsel; prejudice to defendant and a fatal taint on the verdict of death.
At the penalty phase, the prosecutor introduced in aggravation evidence underlying the “attempted murder” of Deputy Sheriff Chris Smith in *964Nevada, including testimony that defendant’s rifle discharged in a struggle with Smith and his alleged admission to his grandmother that “I tried to take one with me.” As the court and counsel knew from before trial had even commenced, defendant had been prosecuted for, and acquitted of, this offense. The prosecutor presented the “attempted murder” of Deputy Smith in his opening statement as a circumstance justifying imposition of the penalty of death. The court admitted evidence relating to the “crime.” The prosecutor called five witnesses to prove the “attempted murder”—two of whom testified about that “crime” and that “crime” alone. He alluded to the “attempted murder” again in his closing argument in asking for the death penalty. The court instructed the jury that it could consider the “crime” (if it found it established beyond a reasonable doubt) in determining whether defendant should live or die, and twice ordered the instruction reread during deliberations in response to requests from the jury. All the while, defense counsel stood by and did nothing.
Penal Code section 190.3 (hereinafter section 190.3) declares in language that is express and unqualified: “[/]« no event shall evidence of prior criminal activity be admitted for an offense for which the defendant was prosecuted and acquitted.” (Italics added.) Thus, the statutory provision bars “evidence of prior criminal activity” underlying “an offense for which the defendant was prosecuted and acquitted” in mandatory and absolute terms as a matter of law. The provision does not bar merely mention of the “label” the offense bore, as the Attorney General claims. It bars evidence of the criminal activity and all the surrounding events.
When I judge his conduct in light of section 190.3, I am compelled to conclude that the prosecutor engaged in separate acts of misconduct by introducing the evidence of the “attempted murder” of Deputy Smith, by presenting it to the jury in his opening statement to support imposition of the penalty of death, and by alluding to it in his closing argument for the same purpose. Of course, it is misconduct for a prosecutor to intentionally introduce statutorily inadmissible evidence. (E.g., People v. Bonin (1988) 46 Cal.3d 659, 689 [250 Cal.Rptr. 687, 758 P.2d 1217].) It is also misconduct to intentionally refer to such evidence in argument. (See, e.g., People v. Ledesma (1987) 43 Cal.3d 171, 238 [233 Cal.Rptr. 404, 729 P.2d 839] (conc. opn. of Mosk, J.).)
I am also compelled to conclude that the court committed separate errors by admitting the evidence of the “attempted murder” of Deputy Smith, by failing to take any steps to prevent or correct the prosecutor’s comments on the “crime,” and by instructing and “reinstructing” the jury that it could take the “offense” into account in the determination of penalty. It is, of course, “the duty of the judge ... to limit the introduction of evidence and *965the argument of counsel to relevant and material matters . . . .” (Pen. Code, § 1044; accord, People v. Ashley (1954) 42 Cal.2d 246, 274 [267 P.2d 271].) Also, . . there is a continuing duty upon the part of the trial court to see to it that the jury are properly instructed upon all matters pertinent to their decision of the cause.’” (People v. Graham (1969) 71 Cal.2d 303, 319 [78 Cal.Rptr. 217, 455 P.2d 153], quoting People v. Keelin (1955) 136 Cal.App.2d 860, 874 [289 P.2d 520, 56 A.L.R.2d 355].) It is clear on the face of the record that the court here failed to discharge its duties with respect to the evidence of the “attempted murder” of Deputy Smith.
In my view, each of the prosecutor’s acts of misconduct and each of the court’s errors must be deemed prejudicial.
To begin with, the balance of circumstances in aggravation and circumstances in mitigation was close. To be sure, the aggravating evidence was substantial. But substantial too was the mitigating evidence. It revealed, for example, that defendant was afflicted with various physical and psychological disorders and disabilities, including organic brain damage; he had suffered abuse at the hands of his stepfather and agemates; he had been a good, loving, and hardworking child and was himself a good, loving, and hardworking father; he evidently had no record of criminal activity antedating the Pizza Bowl offenses; and he was barely 21 years old at the time of the crimes here and was then in great emotional turmoil because of a stormy marriage. The closeness of the case is confirmed by the fact that the jurors deliberated over several days before reaching their verdict and for a time stood at deadlock.
Further, the evidence of the “attempted murder” of Deputy Smith carried within itself a marked potential for upsetting the balance of aggravating and mitigating circumstances to defendant’s detriment. The threat of prejudice inherent in “other crimes” evidence is substantial and notorious. (See, e.g., People v. Robertson (1982) 33 Cal.3d 21, 54 [188 Cal.Rptr. 77, 655 P.2d 279] (plur. opn.) [noting “the overriding importance of ‘other crimes’ evidence to the jury’s life-or-death determination”]; People v. McClellan (1969) 71 Cal.2d 793, 804, fn. 2 [80 Cal.Rptr. 31, 457 P.2d 871] [citing a study showing that “Evidence of a prior criminal record is the strongest single factor that causes juries to impose the death penalty”].) That threat must be deemed to be greater still when, as here, the victim of the “other crime” was a law enforcement officer: such evidence suggests that the defendant is altogether beyond the control of civilized society and can be checked only by means of the ultimate restraint.
In finding no prejudice, the majority conclude that a reasonable juror would not have found beyond a reasonable doubt that defendant attempted *966to murder Deputy Smith and would not have then proceeded to use such a finding to support the penalty of death. I cannot agree.
First, in deliberations one or more of the jurors could have found beyond a reasonable doubt that defendant attempted to murder Deputy Smith. The evidence of the “crime” was more than legally sufficient. Surely, on this record we must answer in the affirmative the question “whether, after viewing the evidence in the light most favorable to the prosecution, any rational trier of fact could have found the essential elements of the crime beyond a reasonable doubt.” (Jackson v. Virginia (1979) 443 U.S. 307, 319 [61 L.Ed.2d 560, 573, 99 S.Ct. 2781].)
Contrary to the majority’s assertion, the evidence introduced by the prosecution on the “attempted murder” of Deputy Smith did not demonstrate that the “circumstances surrounding the shooting” were “ambiguous” or that there was a “substantial chance that the gun discharged accidentally . . . .” (Maj. opn., ante, p. 952.) Indeed, the summary of the evidence which they themselves present shows as much.
Also contrary to the majority’s assertion, the prosecutor’s closing argument did not reveal a “lack of emphasis” (maj. opn., ante, p. 952) on the “attempted murder” of Deputy Smith. As they themselves concede, in closing argument the prosecutor “emphasized [defendant’s] statement to his grandmother that T tried to take one with me.’” (Id. at p. 949.) This statement, of course, was in his view defendant’s admission that he had indeed attempted to murder Deputy Smith.
Finally, contrary to the majority’s assertion, the jurors’ knowledge that defendant had in fact been acquitted of the “attempted murder” of Deputy Smith would not have led them to discount the evidence of the “crime.” If they allowed themselves to make reasonable—or better, realistic—assumptions, the majority would be compelled to conclude that such knowledge would be likely to cause the jurors to adopt the attitude, “Defendant ‘beat the rap’ once before—he will not do it again.”
Second, in deliberations one or more of the jurors could have used the “attempted murder” of Deputy Smith to support the penalty of death. The majority appear to assume that the evidence of the “crime” is not of critical importance on the facts of this case. It is manifest, however, that the prosecutor treated this evidence as crucial: he presented the “attempted murder” in his opening statement and alluded to it in his closing argument, and called five witnesses to prove the “crime”—two of whom testified about that “crime” and that “crime” alone. “There is no reason why we should treat this evidence as any less ‘crucial’ than the prosecutor—and so presumably *967the jury—treated it.” (People v. Cruz (1964) 61 Cal.2d 861, 868 [40 Cal.Rptr. 841, 395 P.2d 889].) Indeed, the jury itself gave clear indication that it considered the evidence of critical importance to its determination: during deliberations, it once requested a rereading of the charge containing the erroneous “other crimes” instruction and once requested a rereading of the erroneous instruction alone. (See People v. Ford (1964) 60 Cal.2d 772, 798 [36 Cal.Rptr. 620, 388 P.2d 892].)
Accordingly, I am of the opinion that there is a reasonable possibility that each of the prosecutor’s acts of misconduct and each of the court’s errors marginally affected to defendant’s detriment the jury’s weighing of aggravating and mitigating circumstances and its consequent determination of the appropriateness of death. Reversal of the judgment as to penalty is therefore required. (See generally People v. Brown (1988) 46 Cal.3d 432, 446-448 [250 Cal.Rptr. 604, 758 P.2d 1135]; id. at pp. 463-470 (conc. opn. of Mosk, J.).)
It may well be, as the majority appear to conclude, that defense counsel “waived” any claims challenging the prosecutor’s misconduct and the court’s admission of the evidence by failing to make any objection whatever, express or implied. But to my mind, “waiver” merely denies a defendant the right to have his claims addressed by us on appeal—it does not deprive us of the authority to reach those claims in the interest of justice in a capital case In any event, claims attacking the court’s instructions are not waived by counsel’s failure to object. (People v. Chavez (1985) 39 Cal.3d 823, 830 [218 Cal.Rptr. 49, 705 P.2d 372]; see Pen. Code, § 1259.) This is so even when, as here, no objection was made to the evidence that is the subject of the challenged instruction. (People v. Hannon (1977) 19 Cal.3d 588, 600 [138 Cal.Rptr. 885, 564 P.2d 1203].)
Even if we could not or would not consider the acts of misconduct and the serious errors identified above, we would be required to reverse the judgment of death on a separate and independent constitutional ground.
Under both the Sixth Amendment to the United States Constitution and article I, section 15, of the California Constitution, a criminal defendant has a right to the assistance of counsel. (E.g., Strickland v. Washington (1984) 466 U.S. 668, 684-685 [80 L.Ed.2d 674, 691-692, 104 S.Ct. 2052] [construing the federal Constitution]; People v. Ledesma, supra, 43 Cal.3d at p. 215 [construing both the federal and state Constitutions].) The right entitles the defendant not to some bare assistance but rather to effective assistance. (Strickland v. Washington, supra, at p. 686 [80 L.Ed.2d at p. 692]; People v. Ledesma, supra, at p. 215.)
*968“A convicted defendant’s claim that counsel’s assistance was so defective as to require reversal of a conviction or death sentence has two components.” (Strickland v. Washington, supra, 466 U.S. at p. 687 [80 L.Ed.2d at p. 693]; accord, People v. Ledesma, supra, 43 Cal.3d at p. 216.)
“First, the defendant must show that counsel’s performance was deficient.” (Strickland v. Washington, supra, 466 U.S. at p. 687 [80 L.Ed.2d at p. 693]; accord, People v. Ledesma, supra, 43 Cal.3d at p. 216.) Specifically, he must establish that “counsel’s representation fell below an objective standard of reasonableness . . . under prevailing professional norms.” (Strickland v. Washington, supra, 466 U.S. at p. 688 [80 L.Ed.2d at pp. 693-694]; accord, People v. Ledesma, supra, 43 Cal.3d at p. 216.)
“Second, the defendant must show that the deficient performance prejudiced the defense.” (Strickland v. Washington, supra, 466 U.S. at p. 687 [80 L.Ed.2d at p. 693]; accord, People v. Ledesma, supra, 43 Cal.3d at p. 217.) “In certain . . . contexts, prejudice is presumed.” (Strickland v. Washington, supra, at p. 692 [80 L.Ed.2d at p. 696]; accord, People v. Ledesma, supra, at p. 217.) Generally, however, it must be “affirmatively prove[d].” (Strickland v. Washington, supra, at p. 693 [80 L.Ed.2d at p. 697]; accord, People v. Ledesma, supra, at p. 217.) To meet this burden, “The defendant must show that there is a reasonable probability that, but for counsel’s unprofessional errors, the result of the proceeding would have been different.” (Strickland v. Washington, supra, at p. 694 [80 L.Ed.2d at p. 698]; accord, People v. Ledesma, supra, at pp. 217-218.) A “reasonable probability” is not a probability that counsel’s failings “more likely than not altered the outcome in the case,” but simply “a probability sufficient to undermine confidence in the outcome.” (Strickland v. Washington, supra, at pp. 693-694 [80 L.Ed.2d at pp. 697-698]; see People v. Ledesma, supra, at p. 218 [to similar effect]).
To my mind, defendant has established his claim of constitutionally ineffective assistance of counsel beyond any doubt whatever.
First, he has shown that defense counsel’s performance was deficient. Failure to make any attempt to keep from the jury evidence of the “attempted murder” of Deputy Smith must be judged to be “representation [falling] below an objective standard of reasonableness . . . under prevailing professional norms.” (Strickland v. Washington, supra, 466 U.S. at p. 688 [80 L.Ed.2d at pp. 693-694].) There was every reason to act and no reason to refrain from acting. Success was certain—the evidence was inadmissible as a matter of law—and could be obtained at absolutely no cost to the defense. Moreover, as stated above the prejudice that the evidence threatened was *969substantial and notorious. (See, e.g., People v. Robertson, supra, 33 Cal.3d at p. 54; People v. McClellan, supra, 71 Cal.2d at p. 804, fn. 2.)
The majority assert that “we have seldom found a mere failure to object to evidence or argument as reflecting counsel’s incompetence.” (Maj. opn., ante, p. 951.) The record, however, requires that we make such a finding here. It plainly reveals that counsel’s failure to act was grounded in their inexcusable ignorance of the express and unqualified prohibition section 190.3 has declared against “evidence of prior criminal activity” underlying “an offense for which the defendant was prosecuted and acquitted.”
Second, defendant has shown that counsel’s deficient performance prejudiced the defense. I am inclined to believe that prejudice should be presumed in the context of this case. I need not, however, decide the issue. This is because defendant has proved prejudice affirmatively. But for counsel’s failings, there is a reasonable probability that the result would have been different: the misconduct and errors identified above would not have occurred and the prejudice they engendered would not have arisen. By allowing such prejudicial misconduct and errors to infect the proceeding, counsel’s deficient performance “undermine[s] confidence in the outcome.” (Strickland v. Washington, supra, 466 U.S. at p. 694 [80 L.Ed.2d at p. 698].) Accordingly, the verdict of death should not stand.
For the foregoing reasons, I would reverse the judgment as to penalty.
Broussard, J., concurred.
Appellant’s petition for a rehearing was denied August 10, 1989.