(concurring in the result).
I join the Chief Justice in affirming Arthur Gary Bishop’s convictions and sentences. However, I cannot agree with the Chief Justice that, with one exception, Bishop’s trial was error-free. The remainder of this opinion explains what errors I think were committed.1 My ultimate conclusion is that all the errors in Bishop’s trial were harmless. For that reason alone, I vote to affirm.
Before proceeding, however, I must observe that given the way the State chose to charge Bishop and to present its case, numerous complex and subtle legal questions were raised. To state that the prosecution or the trial judge may have erred in some particular does not reveal any fundamental flaw in the legal system; it only proves that prosecutors can be over-zealous and that judges are mortal. The crimes charged were of almost inconceivable enormity, and Bishop’s guilt was plain. Yet we must not succumb to the temptation to ignore errors that occurred during trial. To do so would only do a disservice to those who must depend on our opinions for guidance in future cases. The ultimate test of a trial’s fairness is not whether errors were committed, but whether the *493errors were sufficiently harmful to the defendant to require reversal.
My first point of disagreement with the Chief Justice relates to part IX of his opinion. On this point, I agree with Justice Stewart that the manslaughter instruction was erroneous but that the error was harmless.
Second, with respect to part X of the Chief Justice’s opinion, I agree with the analysis in subpart XB that the trial court erred in admitting the three photographs of Graeme Cunningham’s head injuries. See State v. Lafferty, 749 P.2d 1239, 1256-57 (Utah 1988); State v. Cloud, 722 P.2d 750, 752-54 (Utah 1986); State v. Garcia, 663 P.2d 60, 63-64 (Utah 1983); Utah R.Evid. 403. I also agree that any error committed in admitting these photographs was harmless. However, I find the Chief Justice’s opinion lacking in its failure in subpart XA to address the merits of Bishop’s claim that the trial court erred in admitting three other photographs, one each of the remains of Danny Davis, Graeme Cunningham, and Troy Ward, and in the consequent failure of subpart XB to consider whether the State should have stipulated to the contents of those photographs. We should not leave the impression that these photographs were all properly admitted.
Two of the photographs in question show officers removing the bodies of Troy Ward and Graeme Cunningham from a stream. The photographs are of small size and poor quality. In one picture, the corpse is on a litter and is covered with a cloth, except for the legs. It is viewed at some distance, and the most prominent feature in the photograph is the back of the officer carrying the litter. Nothing gruesome or gory is shown. The lighting is such that little can be distinguished besides the officer’s back. The other photograph of a body being removed from the stream also shows only the lower legs. Again, nothing else distinguishable can be seen in the picture except for the back of an officer, and again, there is nothing gruesome or gory about the photograph. The third and final photograph shows Danny Davis’s skeleton as it was being unearthed from its grave. The color photograph shows the top of the head, the torso, and the legs. No flesh is apparent on the bones, which are covered with remnants of the child’s clothing. The view is from the top of the skull down and is unremarkable. The photograph is gruesome, but not markedly so.
In summary, only the photograph of Danny Davis’s skeleton shows anything recognizable as a corpse and raises the concerns expressed in our decisions in State v. Cloud, 722 P.2d at 752-53, State v. Garcia, 663 P.2d at 64, and State v. Wells, 603 P.2d 810, 813 (Utah 1979). Because the two other photographs showing the bodies being removed from the stream do not fall within the gruesome-photographs-of-corpses category that we have subjected to particular scrutiny under rule 403, see State v. Lafferty, at 1256-57, and because they had little potential to unfairly prejudice Bishop, their admission probably was not erroneous under rule 403, even though they had little, if any, probative value.
On the other hand, the photograph of Danny Davis’s skeletal remains presumptively should not have been admitted. Id. Although not unusually gruesome, it certainly did have potential to prejudice the jury unfairly against Bishop. The next question is the probativeness of this picture. How essential was it to the State’s case? See id.; State v. Cloud, 722 P.2d at 753 (citing State v. Garcia, 663 P.2d at 64). The answer is that it was in no way essential to the State’s case. In fact, it is hard to imagine that the photograph was of any assistance in proving the elements of the crime. It did not show the crime scene, nor did it illustrate any issue contested by the parties. It does not show that the boy’s death was brought about by criminal agency. Therefore, the photograph of Danny Davis’s skeleton should have been excluded. Because I conclude that the photograph of Danny Davis’s skeleton should not have been admitted, I would hold that the State should have either done without this photograph or it should have stipulated with the defense as to the relevant facts shown. See part XB of the Chief Justice’s opinion. As noted at the end of this opinion, however, I find the error committed in *494connection with the admission of the photograph of Danny Davis’s skeleton to have been harmless under the unique facts of this case.
My third point of disagreement with the Chief Justice relates to part XII of his opinion. For the reasons set out in Justice Durham’s opinion in State v. Tillman, 750 P.2d 546, 585-88 (1987), I find merit in Bishop’s claim that the jury was not properly instructed as to the need for unanimity on each element of the charge, including the specific aggravating circumstances charged. However, because the jury did return unanimous verdicts on the five separate charges of aggravated kidnapping, which were also charged as aggravating circumstances under the murder counts, the failure to instruct properly on unanimity was harmless.
My fourth and final point of disagreement concerns part XIV of the Chief Justice’s opinion. He would hold that the trial court committed no error in permitting six adolescent boys to testify during the guilt phase of the trial regarding sexual improprieties the defendant had engaged in with them. The purported basis for the introduction of this testimony was section 76-5-404.1(3)(g) of the Code, under which Bishop was charged with sexually abusing Graeme Cunningham. That section provides for enhanced penalties when “[t]he convicted person committed more than five separate offenses under this section....” Utah Code Ann. § 76-5-404.1(3)(g) (Supp.1983) (emphasis added). The statute was amended in 1984, after the abuse of Graeme Cunningham and after Bishop's prosecution had begun, but before the actual trial. The 1984 version substituted “the accused” for “the convicted person.” However, as the Chief Justice notes, Bishop’s case was handled as though the 1983 version governed.
Bishop argues that the trial court misapplied the 1983 version of the statute. Read properly, he contends, the statute required the jury to determine whether he was guilty of sexually abusing Graeme Cunningham before the six boys were allowed to give evidence relevant only to the propriety of an enhanced sentence. Alternatively, Bishop contends that if the statute was correctly construed and applied, then it is unconstitutional because it denied him due process of law. Specifically, if proof of the underlying charge and proof of the enhancing factors are put before the jury at the same time, the presumption of innocence will be undermined and a fair trial will be impossible; the jury will tend to convict because the defendant is a bad person who has committed other acts of abuse, not because the evidence proves he committed the particular crime charged.
On appeal, the State initially agreed that the trial court had misconstrued the 1983 version of the statute and that evidence of the other offenses should not have been introduced before the jury had determined that Bishop was guilty of the underlying sexual abuse charge involving Graeme Cunningham. However, in a supplemental brief the State then retracted this concession, arguing that the trial court properly construed the 1983 version or, alternatively, that the 1984 version should have been used and under its “accused” language, the trial court’s procedure was proper. The State also advanced an alternative ground for the introduction of the testimony, arguing that it tended to prove that Bishop’s motive for the killings was to prevent the victims’ reporting his activities to the police.
The Chief Justice quite properly concludes that there is no merit to the State’s contention that the 1984 statute governs here; the issue must be resolved under the 1983 version alone. However, he then rejects Bishop’s claims. The Chief Justice concludes that the 1983 version of section 76-5-404.1(3)(g) should be read to conform to the 1984 amendments and that under the amendments, simultaneous proof of the underlying crime and the enhancing circumstances is permitted. In response to Bishop’s contention that to so proceed denies due process, the Chief Justice reasons that the legislature has free rein to define the elements of a crime; because it has defined a crime qualifying for enhanced punishment by making proof of five other crimes *495one of the elements, Bishop cannot complain.
Although I agree with the Chief Justice that the 1983 version of the statute applies to this case, I agree with Bishop and the State’s initial brief that the 1983 version of section 76-5-404.1(3)(g) should not be read to permit the order of proof permitted by the trial court. My reasons for this conclusion are several. First, the plain language of the 1983 version appears to contemplate a bifurcated procedure in which guilt of the underlying charge must first be determined; only after the defendant is found guilty can the jury decide whether the “convicted person” has committed more than five other similar offenses. If the legislature had not intended a bifurcated procedure, it is hard to understand why it used the term “convicted person” in the statute.
Second, the procedure permitted by the interpretation the Chief Justice gives the statute is inconsistent with fundamental ev-identiary principles that pervade our law, principles that can rise to the level of constitutional protections. There is no basis for concluding that the legislature consciously intended to contravene these principles when it passed section 76-5-404.1. Finally, the interpretation given the 1983 version of section 76-5-404.1(3)(g) by the trial court almost certainly results in a denial of due process under article I, section 7 of the Utah Constitution. Utah Const, art. I, § 7. It is a settled canon of statutory construction that, when possible, a statute should be interpreted so as to avoid constitutional infirmities. Greaves v. State, 528 P.2d 805, 806-07 (Utah 1974); 2A N. Singer, Sutherland on Statutory Construction § 45.11 (rev. 4th ed. 1984). This due process problem can be avoided by the simple expedient of reading the 1983 version of section 76-5-404.1(3)(g) as written.
A number of sources indicate that permitting proof during the guilt phase of crimes unrelated to that for which the defendant is on trial is inconsistent with fundamental notions of fairness deeply embedded in the law. The law has long been hostile to the introduction of bad character evidence solely for the purpose of proving guilt on a criminal charge. As early as 1896, this Court expressed that hostility when it stated: “The general rule is that one crime cannot be offered to prove a similar offense committed against another person at another time.” People of the Territory of Utah v. Coughlin, 13 Utah 58, 65, 44 P. 94, 95 (1896); accord Boyd v. United States, 142 U.S. 450, 454-58, 12 S.Ct. 292, 294-95, 35 L.Ed. 1077 (1891). In Michelson v. United States, 335 U.S. 469, 69 S.Ct. 213, 93 L.Ed. 168 (1948), the United States Supreme Court explained that this rule is necessary to prevent unfair prejudice:
Courts that follow the common-law tradition almost unanimously have come to disallow resort by the prosecution to any kind of evidence of a defendant’s evil character to establish a probability of his guilt. Not that the law invests the defendant with a presumption of good character, ... but it simply closes the whole matter of character, disposition and reputation on the prosecution’s case-in-chief. The state may not show defendant’s pri- or trouble with the law, specific criminal acts, or ill name among his neighbors, even though such facts might logically be persuasive that he is by propensity a probable perpetrator of the crime. The inquiry is not rejected because character is irrelevant; on the contrary, it is said to weigh too much with the jury and to so overpersuade them as to prejudge one with a bad general record and deny him a fair opportunity to defend against a particular charge. The overriding policy of excluding such evidence, despite its admitted probative value, is the practical experience that its disallowance tends to prevent confusion of issues, unfair surprise and undue prejudice.
Id. at 475-76, 69 S.Ct. at 218-19 (citations omitted). Justice Stewart expressed the same sentiments in his scholarly concurrence in State v. Forsyth, 641 P.2d 1172, 1177-79 (Utah 1982) (Stewart, J., concurring) (cited with approval in State v. Saunders, 699 P.2d 738, 741 n. 17 (Utah 1985), *496and followed without citation in State v. Holder, 694 P.2d 583, 584 (Utah 1984)).
The present Utah Rules of Evidence embody this long-standing common law approach to evidence of prior crimes or bad character. Rule 404(a) states the general rule by forbidding admission of “[ejvidence of a person’s character or a [character] trait ... for the purpose of proving ... [action] in conformity therewith on a particular occasion.” Utah R.Evid. 404(a). Rule 404(a) sets forth several narrow exceptions to this rule, but none are relevant in this case. Rule 404(b), which is identical to Federal Rule of Evidence 404(b), also reflects the law’s cautious approach to such evidence. It permits introduction of evidence of prior crimes or bad acts to prove certain facts relevant to pending charges, but only if the evidence is admissible under rule 403, i.e., only if the danger of unfair prejudice does not outweigh the probative value of the evidence.2 See Fed.R.Evid. 404 advisory committee note to subdivision (b) (cited by Utah R.Evid. 404, advisory committee note); Utah R.Evid. 404(b), 403; Fed.R.Evid. 404(b), 403.
This Court’s decisions have consistently recognized that an accused is almost certainly prejudiced unfairly when evidence of unrelated crimes or bad acts is introduced because of “the tendency of a fact finder to convict the accused because of bad character rather than because he [or she] is shown to be guilty of the offenses charged.” State v. Saunders, 699 P.2d at 741. For this reason, “such evidence is presumed prejudicial and, absent a reason for the admission of the evidence other than to show criminal disposition, the evidence is excluded.” Id.
This hostility to bad character evidence is manifested in our cases imposing a requirement that trial courts make every effort to avoid the introduction of such evidence at a trial on an unrelated criminal charge. For example, when the prosecution joins two or more charges, but evidence of each crime would not otherwise be admissible at a trial for the other, we require that the charges be severed for trial. See State v. Long, 721 P.2d 483, 495 (Utah 1986) (suggesting that on retrial charges of possession of a dangerous weapon by a restricted person should be severed from charges of aggravated assault and attempted murder because of “unwarranted prejudice inherent in informing the jury that a defendant is a convicted felon”); State v. Tarafa, 720 P.2d 1368, 1370 (Utah 1986) (joint trial of theft charges arising out of three separate but similar incidents held denial of due process; remanded for separate trials); State v. Saunders, 699 P.2d at 741 (joint trial of charge of possession of a firearm by restricted person with charges of burglary and theft held unduly prejudicial; remanded for separate trials); State v. McCumber, 622 P.2d 353, 356 (Utah 1980) (joint trial on aggravated sexual assault and similar charges arising out of unrelated criminal episodes held a denial of due process; remanded for separate trials); State v. Gotfrey, 598 P.2d 1325, 1328 (Utah 1979) (joint trial of one sodomy and two rape charges arising out of three separate instances denied fair trial; remanded for separate trials).
In the same vein, we have required that evidence of other crimes or bad acts be excluded whenever possible because of its great potential for unfair prejudice. See State v. Holder, 694 P.2d at 585 (admission of evidence of robbery at trial for theft of car held abuse of discretion under rule 45 (predecessor to rule 403) because potential for unfair prejudice outweighed probative value; remanded for new trial).
In the present case, the only justification for admitting in the guilt phase evidence of six other instances of sexual abuse is that section 76-5-404.1(3)(g) made commission of more than five such acts an element that must be proven before a convicted person is eligible for an enhanced penalty. The Chief Justice concludes that this section effectively authorized simultaneous admis*497sion of evidence relevant to an enhanced sentence and evidence of guilt of the underlying charge. Absent such authorization, rule 404(a) would have required exclusion of the evidence because it was not part of the criminal episode from which the underlying sexual abuse charge arose and it did not satisfy any of the exceptions listed in rule 404(a) or (b).3 Yet the Chief Justice, in seeking the appropriate construction of section 76-5-404.1(3)(g), does not appear to have considered the deep and long-standing hostility of Utah law to such a use of evidence of unrelated criminal activity. I think that in the absence of a clear indication that the legislature intended a different result for a good reason, we should not interpret a statute to reach such a result. Therefore, I reject the Chief Justice’s interpretation of the 1983 version of section 76-5-404.1(3)(g).
There is another reason for not reading the statute as the Chief Justice suggests. Such a reading renders the statute unconstitutional. Language in some of our cases, such as State v. Saunders and State v. Tarafa, plainly states that permitting the jury to consider otherwise inadmissible bad character evidence for the sole purpose of determining guilt denies a defendant due process in violation of the state and federal constitutions. See, e.g. Tarafa, 720 P.2d at 1370; Saunders, 699 P.2d at 741-42; State v. McCumber, 622 P.2d at 356.4 That would be the precise effect of permitting section 76-5-404.1 to be read as it was by the trial court.
As indicated above, Bishop has a fundamental interest in having his guilt on the underlying charge of sexual abuse determined in an atmosphere free from the almost overwhelming prejudice that arises when evidence of more than five other unrelated instances of sexual abuse is introduced during the guilt phase. On the other hand, the legislature has a legitimate interest in providing for enhanced punishment for those with a history of criminal conduct. See, e.g., State v. Bailey, 712 P.2d 281, 286-87 (Utah 1985). One expression of that interest is section 76-5-404.1(3)(g). But pursuit of that legitimate interest in no way requires that evidence relevant to enhanced punishment be introduced in the guilt phase of a trial on the underlying charge, where it is almost certain to unfairly prejudice that trial.
The Chief Justice suggests that the admission of what would otherwise be inadmissible bad character evidence is permissible in this case simply because the legislature has chosen not only to make evidence *498of other crimes a prerequisite for eligibility for an enhanced penalty, but also to permit eligibility to be determined in the guilt phase of the trial. As noted, I do not agree that the legislature has sanctioned such a procedure. But even if it had, the due process question remains: Can the legislature require that unrelated factual questions be determined in one proceeding when such an aggregation of issues is not necessary to accomplish a legitimate legislative objective and when it unfairly prejudices the accused? I think not, consistent with the due process clause of article I, section 7 of the Utah Constitution and our decisions in Tarafa, Saunders, and McCumber, among others. Here, there is no need to combine the question of guilt and enhancement in one proceeding because each question is independent of the other and could readily be determined separately. And no other legitimate legislative objective requiring joint determination of these issues has been suggested.5 Therefore, I conclude that the procedure followed by the trial court operated to deny Bishop his due process rights under the Utah Constitution. Because we should interpret a statute to avoid constitutional infirmities, this analysis also supports my conclusion that section 76-5-404.1(3)(g) should not be read to permit such an aggregation of issues and evidence.
How then is a court to proceed, consistent with due process, to determine the questions of guilt and eligibility for enhancement under section 76-5-404.1? The legitimate interests of the State and the accused can easily be accommodated through a bifurcated procedure. When the underlying crime is charged, and enhancing circumstances involving other crimes or bad acts factually unrelated to the underlying criminal episode are also charged for the purpose of increasing the severity of the punishment for the underlying crime, the trial court must divide the trial into separate segments. First, evidence regarding the underlying crime should be admitted, and the jury should be asked to determine guilt or innocence based on that evidence alone. Second, if a guilty verdict is returned on the underlying charge, then evidence regarding the enhancing circumstances should be heard by the same jury for the purpose of determining whether those circumstances have been proven beyond a reasonable doubt.6 Only if the jury finds that the circumstances have been proven would the “convicted person” receive the enhanced penalty.7
I recognize that the 1984 version of section 76-5-404. l(3)(g) deleted the reference to the “convicted person” and therefore does not lend itself readily to the interpretation I find appropriate for the 1983 version. However, as the Chief Justice observes, the legislature did not intend the 1984 amendments to change the 1983 version. And the 1984 version, if construed in accord with the Chief Justice’s interpretation of the 1983 version, would be subject to the same constitutional infirmities. For *499these reasons, I would construe the 1984 version as also requiring a bifurcated procedure.
It is worth observing that, as a general matter, requiring that trials proceed in the bifurcated fashion described above is entirely within our inherent power to supervise the courts. It is especially appropriate that we exercise that supervisory power to require certain procedures when fundamental values are threatened by other modes of proceeding. See, e.g., State v. Lafferty, at 1260 (imposing requirement of instructions and written findings on proof of aggravating circumstances in penalty phase of capital case); Smith v. Smith, 726 P.2d 423, 425-26 (Utah 1986) (imposing requirement of detailed findings and reasons for decree awarding custody); State v. Long, 721 P.2d at 492 (imposing requirement for eyewitness identification instruction); State in re Clatterbuck, 700 P.2d 1076, 1081 (Utah 1985) (imposing requirement of detailed findings and reasons for certifying juveniles to stand trial as adults).8
The final and overarching question presented by my conclusion that several errors were committed in the trial of this case is whether the errors were harmless. Two standards for determining the “harmlessness” of an error may apply to this case. The first is the standard set by our rules to determine whether a particular error warrants reversal. The second is the standard fixed by the United States Supreme Court for violations of the federal constitution. The standard applicable under our rules is settled. Rule 30 of the Utah Rules of Criminal Procedure states, “Any error, defect, irregularity or variance which does not affect the substantial rights of a party shall be disregarded.” Utah R.Crim.P. 30(a). A slightly different wording is used in Utah Rule of Evidence 103, which also applies in criminal proceedings. That rule provides, “Error may not be predicated upon a ruling which admits or excludes evidence unless a substantial right of the party is affected....” Utah R.Evid. 103(a). We consider these two rules to set substantively identical standards. State v. Hackford, 737 P.2d 200, 204 n. 1 (Utah 1987). Compare State v. Knight, 734 P.2d 913, 919-20 (Utah 1987), with State v. Rammel, 721 P.2d 498, 500 (Utah 1986). An error requires reversal under this standard if our “confidence in the outcome” of a particular trial is “eroded.” Knight, 734 P.2d at 920. Only when confidence in the outcome is eroded can we say that, absent the error, there is a reasonable likelihood that the outcome would have been more favorable to the defendant. Id. at 919-20.
Under this standard, I have absolutely no difficulty in concluding that all the errors discussed above were harmless. The Graeme Cunningham photographs were very gruesome and had significant power to inflame the jury and unfairly prejudice Bishop. The testimony of the six boys had a strong tendency to convince the jurors that Bishop is a loathsome, confirmed child abuser and to deprive them of the ability to appraise the evidence against him fairly. In any other situation, the admission of these items of evidence almost certainly would mandate reversal. This case, however, is unusual. Bishop made a detailed confession. A reading of that confession leaves me with a firm and unshakeable conviction that the verdicts on the five *500counts of capital homicide, the five counts of aggravated kidnapping, and the count of sexual abuse of a child would have been the same even if the trial court had kept out the objectionable photographs and had prevented the six boys from testifying during the guilt phase. I am similarly convinced that the result in the penalty phase would have been the same in the absence of these errors.
An additional word is necessary with respect to the sexual abuse of a child charge. If there had been any substantial conflict in the evidence supporting the charge of sexually abusing Graeme Cunningham, I would conclude that the introduction of the testimony of the six boys before the jury had determined guilt on the sexual abuse charge would have been harmful error and would require reversal. However, the evidence that the Cunningham boy was induced by Bishop to pose for sexually explicit nude photographs came directly from his confession and was uncontested. Because I agree with the Chief Justice that this evidence supports a conviction for sexual abuse of a child, I conclude that the testimony of the other six boys was harmless error under the “erosion of confidence” standard.
The second or federal constitutional harmless error standard is also pertinent in this case. Bishop raises several claims based on the state and federal constitutions in challenging the admission of the testimony of the six boys during the guilt phase of the trial on the sexual abuse charge. As noted above, there is no need to reach the merits of Bishop’s federal due process contentions because I find that the trial court’s mode of proceeding was contrary to the statute’s language and violated the Utah Constitution’s due process clause, article I, section 7. However, the fact that I find error in the trial court’s procedure without reaching Bishop’s federal constitutional claims does not permit me to ignore those claims unless the standard used to determine the harmfulness of state constitutional violations is at least as strict as the federal constitutional error standard. If it is not as strict, it is possible that a state constitutional error could be found to be harmless when an analogous federal constitutional error would not.
This court has yet to squarely decide whether the harmless error standard applicable to violations of the state constitution is the erosion of confidence standard or the stricter federal “harmless beyond a reasonable doubt” standard. State v. Hackford, 737 P.2d at 204-05 & n. 3. And there is no reason to reach that issue today. It is sufficient to assume, arguendo, that Bishop’s claims attacking the unitary procedure which permitted the introduction of the six boys’ testimony during the guilt phase would be resolved in his favor under the federal constitution just as they have been under the Utah constitution and to analyze the errors under the federal harmless error standard. If the errors are still found to be harmless, there is no need to decide the merits of Bishop’s federal claims because they would not affect the outcome.
As indicated in Hackford, the current articulation of the federal constitutional harmless error standard requires a reversal unless “the overwhelming evidence” shows that the result would have been no different in the absence of the error. 737 P.2d at 205 n. 3; see State v. Tillman, at 555. In the present case, I find this standard satisfied with respect to all of the charges. Again, a reading of the confession is sufficient to convince me, beyond a reasonable doubt, that the jury would have convicted Bishop of all charges whether or not the six boys had been permitted to testify during the guilt phase. Despite all the prosecution’s questionable efforts to enliven the trial with grisly photographs, bits of clothing from the skeletons, and emotional testimony from the victims’ relatives, the cold words of the confession, revealing crimes of singular monstrosity, remain the most compelling evidence against Bishop and make it inconceivable that he would have been acquitted on any of the charges.
My conclusion with respect to the sentencing phase is the same. Even if the bifurcated procedure that I outline had been followed, the jury would have heard the boys’ testimony before it decided to impose the death sentences. Had it not *501been admitted to enhance the penalty for the sexual abuse of a child charge, the jury could have considered it as evidence of aggravating circumstances to be weighed in deciding whether to impose the death sentences. See Utah Code Ann. §§ 76-3-207(2), (3) (Supp.1987); State v. Lafferty, 749 P.2d at 1259-60 (allowing other violent crimes to serve as aggravating circumstances if proven beyond a reasonable doubt); cf. Gregg v. Georgia, 428 U.S. 153, 206-07, 96 S.Ct. 2909, 2940-41, 49 L.Ed.2d 859 (1976) (Georgia statute permitting jury to consider any aggravating circumstance upheld); Harris v. Pulley, 692 F.2d 1189, 1194 (9th Cir.1982) rev’d on other grounds, 465 U.S. 37, 104 S.Ct. 871, 79 L.Ed.2d 29 (1984) (California statute permitting jury to consider non-statutory aggravating circumstances upheld). But even if this testimony had not been admitted, the overwhelming weight of the other evidence leads me to conclude beyond any doubt that the jury would have imposed five death sentences on Bishop.
For the foregoing reasons, I conclude that the errors were harmless under any applicable standard. The convictions and sentences should be affirmed.
. Because two other justices join in this opinion with minor reservations, it expresses the view of the majority of the Court on most of the issues it addresses, with the exception of those issues specifically noted in the opinions of Associate Chief Justice Stewart and Justice Durham.
. Rule 609(a) also embodies the law’s general hostility to evidence of bad acts or bad character offered to prove guilt. It provides that evidence of a prior conviction may not be admitted to impeach a witness unless "the court determines that the probative value of admitting this evidence outweighs its prejudicial effect_” Utah R.Evid. 609(a).
. Utah Rule of Evidence 404(b) forbids the admission of evidence of "other crimes, wrongs or acts ... to prove the character of a person in order to show that he acted in conformity therewith.” However, it does permit the introduction of such evidence for "other purposes,” including "proof of motive.” Utah R.Evid. 404(b). The State relies on this exception to justify the admission of the six boys’ testimony, arguing that it tended to show that Bishop’s motive for the killings was to prevent disclosure of his activities. This argument must fail. The advisory committee’s note to Utah Rule of Evidence 404 cites the advisory committee’s note to the identical federal rule, which states that relevancy alone does not make evidence admissible under one of the exceptions; the trial court still must find that the potential for unfair prejudice does not substantially outweigh the probative value. Fed.R.Evid. 404(b) advisory committee note.
In State v. Holder, 694 P.2d 583, 584 (Utah 1984), this Court made it clear that such a determination must be made under the Utah rule as well. Under the facts of the present case, that analysis would result in the exclusion of the evidence. The testimony of the boys was essentially cumulative of evidence that had already been admitted from Bishop’s confession and from one witness. Therefore, its probative value as to his motive for the killings was minimal, an important factor in making the admissibility determination. See Fed.R.Evid. 404(b) advisory committee note. On the other hand, the potential for unfair prejudice was enormous, raising a real possibility that the jury would convict on the basis of the other uncharged crimes, rather than the one actually charged. Therefore, the evidence did not qualify for admission under the rule 404(b) exceptions.
. Most of our other cases do not reach the constitutional question. They simply hold that when bad character evidence is admitted as an element of a crime, the trial court should make every effort to insulate the jury from hearing such evidence while considering other unrelated charges. See, e.g., State v. Long, 721 P.2d 483, 495 (Utah 1986); State v. Gotfrey, 598 P.2d 1325, 1328 (Utah 1979). These decisions certainly do not contradict those grounded on statements regarding constitutionality.
. I can conceive of no constitutionally legitimate interest that could be vindicated by a statute which permitted the introduction of evidence of unrelated crimes during the guilt phase solely for the purpose of proving the defendant guilty of the underlying charge.
. The Chief Justice’s opinion justifies the eviden-tiary procedure used in the trial court as protecting a defendant’s interests by ensuring that the enhancing factors will be proven to the jury beyond a reasonable doubt and under the rules of evidence. However, those protections are better provided by the required bifurcated procedure, which also eliminates the unfair prejudice to a defendant inherent in the procedure followed by the trial court. Cf. State v. Lafferty, 749 P.2d 1239, 1260 & n. 16 (Utah 1988) (adopting procedural requirements to ensure that other violent crimes cannot serve as aggravating factors in the penalty phase of a capital case, unless they have been proven beyond a reasonable doubt).
.If the facts that support the enhancing charge are part of the criminal episode out of which the basic charge arose, whether measures should be taken to separate proof of the underlying charge from proof of the enhancing facts is a matter left to the trial court’s discretion. Of course, the trial court should exercise its discretion in a manner consistent with our strong concerns about unnecessarily tainting the finder of fact with evidence of other bad acts. See State v. Long, 721 P.2d at 495; State v. Tarafa, 720 P.2d 1368, 1370 (Utah 1986); State v. Saunders, 699 P.2d 738, 741-42 (Utah 1985). However, when there is no such relationship between the basic charge and the enhancing facts, bifurcation is mandatory.
. The legislature has also defined the elements of certain other crimes to include unrelated bad acts solely for the purpose of enhancing punishment. For example, a knowing or intentional killing not committed under any of the circumstances listed in section 76-5-202 of the Code constitutes second degree murder and is punishable by imprisonment for five years to life. Utah Code Ann. §§ 76-5-203(l)(a), 76-3-203(1) (Supp.1987). However, if a knowing or intentional killing is committed by one who has previously been convicted of "first or second degree murder or of a felony involving the use or threat of violence to a person” or by one "under a sentence of life imprisonment or a sentence of death,” then that killing may be punishable by death. Utah Code Ann. § 76-5-202(l)(h), (p) (Supp.1987). The introduction in the guilt phase of a murder trial of evidence of a prior murder conviction would raise all the concerns presented in this case. The bifurcated procedures described here would be equally appropriate in the trial of such cases. Cf. State v. Lafferty, at 1260 (establishing procedures for admitting in the penalty phase of a capital trial evidence of other violent crimes for which convictions have not been obtained).