¶ 13. {concurring). I join fully in the Majority Opinion, but write separately to discuss two matters to which the Majority alludes: (1) the prosecutor's extortion of Edward Bannister's agreement to let the jury know that Michael Wolk died from an overdose of morphine, and (2) the prosecutor's basing his opening statement in part on Steven Wolk's projected testimony when on this Record there is nothing to show that the prosecutor had a good-faith basis to believe that *369Steven Wolk would not claim his Fifth Amendment privilege to not testify. I discuss these in turn.
(1) Michael Wolk's death.
¶ 14. As the Majority notes, although the State originally charged Edward Bannister with unlawful delivery of morphine, see Wis. Stat. §§ 961.14(3) & 961.41(l)(a), and first-degree reckless homicide, see Wis. Stat. § 940.02(2) (death resulting from the unlawful delivery of a controlled substance), on the morning of the first trial day, the prosecutor said that he would not pursue the homicide charge if Bannister agreed that the prosecutor could let the jury know that Michael Wolk died from a morphine overdose. Bannister's lawyer objected, and noted that the lead prosecutor had told him earlier that the State did not believe it had sufficient evidence to prove the reckless-homicide charge, and that the threat to file an amended information charging only first-degree reckless homicide was thus, as phrased by Bannister's lawyer, "just an end run attempt" to get the evidence of death before the jury. When the trial court said that it would permit the prosecutor to file a single-count amended information charging Bannister with first-degree reckless homicide, Bannister decided to let the prosecutor tell the jury that Michael Wolk died from a morphine overdose.
¶ 15. Later, in his opening statement to the jury, the prosecutor emphasized Michael Wolk's overdose death, relating how Wolk's wife found him dead in their living room:
And the purpose of the testimony regarding the death is not [sic] ask someone to answer for that death, but it's an important element of evidence that I think that you have to listen to. So although it may be painful to listen to it, it may not be the nicest evidence you'll *370hear. It's important. It's important because his wife found him, what ends up, being dead.
The prosecutor then told the jury that the Milwaukee medical examiner and a toxicologist working in his office would testify that Michael Wolk died on January 17, 2003, from an overdose of morphine that he ingested either that day or the night before, but that the prosecutor was "not asking" the jury "to make a determination who is at fault for Michael Wolk's death. I don't know who is at fault for that death. I know who is at fault for giving him, several days before, some morphine and selling it to him, and that's this defendant right here." (Emphasis added.) In my view, all of this was highly improper.
¶ 16. First, a lawyer may never tell a jury what the lawyer knows about the contested issues in a case. Supreme Court Rule 20:3.4 is not only explicit: "A lawyer shall not: ... (e) in trial,... assert personal knowledge of facts in issue except when testifying as a witness, or state a personal opinion as to the justness of a cause,... or the guilt... of an accused," but, indeed, this is law-school 101. Frankly, it is shocking that this lawyer, Milwaukee County assistant district attorney Denis Stingl, apparently did not know that, or, if he did know it, ignored the proscription nevertheless. But that is not all.
[A prosecutor] is the representative not of an ordinary party to a controversy, but of a sovereignty whose obligation to govern impartially is as compelling as its obligation to govern at all; and whose interest, therefore, in a criminal prosecution is not that it shall win a case, but that justice shall be done. As such, he is in a peculiar and very definite sense the servant of the law, the twofold aim of which is that guilt shall not escape or innocence suffer. He may prosecute with earnestness and vigor — indeed, he should do so. But, *371while he may strike hard blows, he is not at liberty to strike foul ones. It is as much his duty to refrain from improper methods calculated to produce a wrongful conviction as it is to use every legitimate means to bring about a just one.
Berger v. United States, 295 U.S. 78, 88 (1935). Although as contended by the State in oral argument on this appeal, Michael Wolk's death from a morphine overdose was evidence of his recent ingestion of morphine (while the traces found in his house could have been left there at almost any time), that fact was not relevant because Bannister's confession (the only "evidence" tying Bannister to morphine in Michael Wolk's house) encompassed mid-December 2002 to mid-January 2003, and the morphine that caused Michael Wolk's death could have been gotten by him at any time — even before December of 2002. In any event, the solution was to ask for an agreement that Michael Wolk possessed morphine in mid-January 2003 without telling the jury that he died as a result. Waving the "bloody shirt" of Wolk's overdose death invited — in the most blatant way — the jury to consider the evidence as proving that, beyond the delivery-charge, Bannister was also guilty of homicide.1 Thus, the prosecutor's "warning" to the jury that "the purpose of the testimony regarding the death is not [sic] ask someone to answer for that death, but it's an important element of evidence that I think that you have to listen to" was disingenuous *372and not befitting the important role for justice that prosecutors have in our system. Indeed, it is a perfect example of the apophasis rhetorical device — arguing something by disclaiming an attempt to so argue. The prosecutor's opening-statement dance was, as Justice Felix Frankfurter noted in a somewhat related context, akin to "the Mark Twain story of the little boy who was told to stand in a corner and not to think of a white elephant." Leviton v. United States, 343 U.S. 946, 948 (1952) (mem. of Frankfurter, J.).
(2) Steven Wolk's non-testimony.
¶ 17. As the Majority recounts, the prosecutor told the jury that Steven Wolk, Michael Wolk's brother, would testify that they both got morphine from Bannister in mid-January:
I'm asking, for instance, if Steven [Wolk] should testify, you listen to him and you weigh his evidence and you weigh his credibility. It'll be out there for you. You may find he's a distasteful individual. He's a drug user. His brother was a drug user. Drugs kñled his brother. You'll hear— it'll be clear that Steven Wolk isn't the nicest person in the world but he's a witness to what happened.
He'll tell you that over a span of time, that he and his brother, together with Steven, would obtain morphine from the defendant, Edward Bannister. It went on for about a year. They would go to Edward Bannister's home and obtain it. Sometimes, Edward Bannister would give it to him, according to Steven. I don't know if that's true— but one thing, you have to weigh everything— would give it to him free of charge. Sometimes, he'd give him some good faith money. That on or about the 14th or 15th of January, he can't remember the exact day, sometime in late morning or early afternoon, Steven Wolk, Michael Wolk went to the *373defendant's home and the defendant gave them two tablets of morphine, that they in turn gave the defendant $20.00 in exchange for that, and that Steven took one pill and Michael took another one of the pills so that they could use it at a later date or later time.
(Emphasis added.)
¶ 18. Steven Wolk never testified. Rather, when he was ostensibly supposed to testify, .he and his lawyer told the trial court that Steven Wolk would invoke his Fifth Amendment privilege to not testify. When Bannister's lawyer asked the trial court whether he could refer in his closing argument to the fact that despite the prosecutor's assertions in his opening statement about what Steven Wolk would tell the jury, the State never produced Steven Wolk to the jury, the prosecutor complained that that would be unfair because, among other things, "I mentioned him as a potential witness. You will maybe hear from him or about him." (Emphasis added.)
¶ 19. The trial court ruled that not only could Bannister's lawyer not tell the jury that Steven Wolk asserted his Fifth Amendment privilege, see Wis. Stat. Rule 905.13(1) (In criminal cases, "[t]he claim of a privilege, whether in the present proceeding or upon a prior occasion, is not a proper subject of comment by judge or counsel."), but, also, and this is the crux, forbade Bannister's lawyer from arguing that the prosecutor did not keep his promise about what Steven Wolk would testify, ruling: "I don't think you should reference him as failing to be a reference [sic]."2 In my view, this was error.
*374¶ 20. A prosecutor's use of non-evidence (such as assertions in an opening statement or, under some circumstances, questions) to sway a jury, can deny a defendant his or her right to confrontation when those assertions are not backed by evidence produced at trial. Douglas v. Alabama, 380 U.S. 415, 418-420 (1965) (defendant denied right to confrontation when prosecutor's statements and questions, although "not technically testimony," were the equivalent in the jury's eyes, thus triggering the right to confront). Of course, not every opening-statement promise of proof that is not validated by evidence is a prejudicial denial of the confrontation right. See Frazier v. Cupp, 394 U.S. 731, 733-737 (1969) (de minimis effect on trial and prosecutor's good faith belief that evidence could be produced) ("Certainly not every variance between the advance description and the actual presentation constitutes reversible error, when a proper limiting instruction has been given."). There is nothing in the Record here, unlike the situation in Frazier, 394 U.S. at 733, that indicates that the prosecutor in this case tried to determine ahead of time that Steven Wolk would testify and that the prosecutor was misled by Steven Wolk's last-minute change of heart. Indeed, when the trial court prevented him from telling the jury that Steven Wolk did not testify, Bannister's lawyer pointed out that whether Steven Wolk would or would not testify "could have been asked of him a longtime ago." The trial court, however, excused the prosecutor's failure to find out if Steven Wolk would testify by noting that Steven Wolk was in prison. The prosecutor, tacitly admitting that he did not bother to find out, replied that any assurance Steven Wolk could have given him would have been transitory because "he can change his mind up to the very moment."
*375¶ 21. Further, and working synergistically with the defendant's right to confront his or her accusers, is the rule that no party, especially a prosecutor in a criminal case, may promise to prove something that he or she knows, or reasonably should know, cannot be proven by evidence at trial. See ABA Standards for Criminal Justice: Prosecution Function and Defense Function, Standard 3-5.5 Opening Statement (3d ed. 1993) ("The prosecutor's opening statement should be confined to a statement of the issues in the case and the evidence the prosecutor intends to offer which the prosecutor believes in good faith will be available and admissible. A prosecutor should not allude to any evidence unless there is a good faith and reasonable basis for believing that such evidence will be tendered and admitted in evidence.") (emphasis added).
¶ 22. It is no answer to say that the trial court told the jury that the lawyers' arguments were "not evidence" — the jury heard the prosecutor's version of what Steven Wolk would tell them, and that went unrebutted when the trial court refused to allow the defense lawyer to even remind the jury that it was a prosecutorial promise not kept. Indeed, as we have already seen, the prosecutor also improperly told the jury that he "knew" that Bannister had given morphine to Michael Wolk "several days before" Wolk's death on January 17, and that was the precise piece of the puzzle that the prosecutor promised the jury would be supplied by Steven Wolk.
¶ 23. We indulge the presumption that juries follow instructions because that advances the goals of finality. If we did not, we'd be trying the same case over and over again — the jurisprudential equivalent of a structure drawn by Maurits C. Escher. Yet, we must not let this general rule blind us to the rare situation when *376the trial court's instructions do not cure the prejudice. As Learned Hand repeatedly warned, the efficacy of the instructions are more assumed than real. See United States v. Delli Paoli, 229 F.2d 319, 321 (2d Cir. 1956) ("Possibly it would be extreme to say that nobody can ever so far control his reasoning that he will not in some measure base his conclusion upon a part of the relevant evidence before him, which he has been told to disregard; but at least it is true that relatively few persons have any such power, involving as it does a violence to all our habitual ways of thinking."), aff'd, 352 U.S. 232; Nash v. United States, 54 F.2d 1006, 1007 (2d Cir. 1932) (Instruction to jury to ignore prejudicial evidence often requires them to perform "a mental gymnastic which is beyond, not only their powers, but anybody's else."), cert. denied, 285 U.S. 556. Here, Steven Wolk's projected testimony was the key link tying Bannister to the delivery of any morphine to Michael Wolk, no less the delivery of morphine to Michael Wolk several days or so before January 17.
(3) Conclusion.
¶ 24. If the prosecutor believed he could prove that Bannister had given Michael Wolk the morphine that caused Michael Wolk's death, he should have stayed with the first-degree-reckless-homicide charge and let the jury decide Bannister's guilt or innocence on that charge. If the prosecutor did not believe that he could prove that Bannister had given Michael Wolk the morphine that caused Michael Wolk's death, then his back-door use of the death-evidence was improper. Further, any lawyer, especially prosecutors, whose jobs are, as we have discussed, to seek justice and not merely convictions, should never promise in their opening statements to prove something unless they are certain *377that the evidence is both available and admissible. Trial judges, as impartial arbiters of justice, must ensure that this is done, and use appropriate judicial power if it is not. Additionally, institutional law offices, such as the district attorney's office, have a special responsibility to ensure that the lawyers they send into court follow the simple rules of evidence, ethics, and fairness. Sadly, none of this was done here.
According to the Wikipedia online encyclopedia: "The term 'bloody shirt' can be traced back to the aftermath of the murder of the third Caliph, Uthman in 656 CE, when a bloody shirt and some hair alleged to be from his beard were used in what is widely regarded as a cynical ploy to gain support for revenge against opponents." Wikipedia, http://en.wikipedia.org/ wiki/Bloody_shirt.
Most likely the trial court said "witness" but this was mistranscribed as "reference."