895 P.2d 359 (1995)

STATE of Utah, Plaintiff and Appellee,
v.
Tomas R. HERRERA, Defendant and Appellant.
STATE of Utah, Plaintiff and Appellee,
v.
Mikell SWEEZEY, Defendant and Appellant.

Nos. 920209, 920265.

Supreme Court of Utah.

April 21, 1995.

*360 R. Paul Van Dam, Atty. Gen., Christine Soltis, Asst. Atty. Gen., Salt Lake City, for plaintiff.

Joan C. Watt, Mark R. Moffat, Richard P. Mauro, Salt Lake City, for Herrera.

Lisa J. Remal, Joan C. Watt, Salt Lake City, for Sweezey.

*361 HOWE, Justice:

This is an appeal from two interlocutory orders entered in two cases which we have consolidated for appellate purposes. Defendants Tomas R. Herrera and Mikell Sweezey both challenge the constitutionality of Utah's insanity defense as codified under Utah Code Ann. ง 76-2-305 and other related sections.

FACTS

Since this is an interlocutory appeal, there has been only limited adjudication of the specific facts in either case. The State concedes the following facts only so far as the limited issue of constitutionality is concerned.

State v. Herrera

Defendant Herrera shot and killed his ex-girlfriend, Claudia Martinez. He admitted to the police that he had been visiting "some girl" when "something snapped, something happened to him and he decided to go to the Martinez house and shoot Claudia." He also admitted that he took his gun to her home and shot her twice in the head. He then chased her mother, Rosa Gonzales, into a bedroom where Claudia's brother, Reuben Martinez, was sleeping. Herrera shot at both of them but missed. The police arrested Herrera shortly after the killing while he still had possession of the gun. He had not consumed any alcohol or drugs. He was charged with Claudia's murder and with the attempted murder of the other two, all in violation of Utah Code Ann. ง 76-5-203.

Herrera eventually pleaded not guilty by reason of insanity. He filed several motions attacking Utah's statutory scheme as unconstitutional. The trial court upheld the insanity defense statutes, and Herrera petitioned for this interlocutory appeal.

State v. Sweezey

Steve Matthews was standing outside a hotel in downtown Salt Lake City when Sweezey approached. When Sweezey was within about eight feet, he pulled a gun from his backpack and shot Matthews in the face. The bullet entered Matthews's left cheek but did not kill him. A security officer of the hotel heard Sweezey say, "They wrecked my home so I shot him." Sweezey was charged with attempted murder in violation of Utah Code Ann. ง 76-5-203.

Sweezey also filed several motions that are essentially identical to those filed by Herrera, attacking Utah's insanity defense statutes. The trial court denied these motions, and we granted Sweezey's interlocutory appeal.

STANDING ISSUES

Initially, there is a question whether either Herrera or Sweezey, at this early stage, has demonstrated that he has standing to challenge the statutes. However, it is an adequate showing of standing if an expert provides testimony or an affidavit asserting that a "viable issue of insanity" is involved in the case. State v. Rhoades, 119 Idaho 594, 809 P.2d 455, 459-60 (1991). Both Herrera and Sweezey presented such testimony, and we conclude that they have standing to bring this challenge.

ANALYSIS

I. Background

When John Hinckley was found not guilty by reason of insanity for shooting President Ronald Reagan and Press Secretary James Brady, public outrage prompted Congress and some states to reexamine their respective insanity defense laws. As a result, in 1983 Utah abolished the traditional insanity defense in favor of a new statutory scheme. State v. Young, 853 P.2d 327, 383 (Utah 1993); Utah Legislative Survey, 1984 Utah L.Rev. 115, 151. Under Utah's current scheme:

It is a defense to a prosecution under any statute or ordinance that the defendant, as a result of mental illness, lacked the mental state required as an element of the offense charged. Mental illness is not otherwise a defense.

Utah Code Ann. ง 76-2-305(1). This amendment eradicated the prior law, which allowed a defendant to present an independent affirmative defense of insanity. In other words, the former statute permitted a defendant to defend on the ground that he or she committed *362 the act but did not understand that the act was wrong. The new law limits the defense to simply that the defendant did not have the requisite mens rea of the alleged crime. Young, 853 P.2d at 384.

A common example is helpful to illustrate the difference between the prior law and the new law. If A kills B, thinking that he is merely squeezing a grapefruit, A does not have the requisite mens rea for murder and would be acquitted under both the prior and the new law. See Wayne R. LaFave, Substantive Criminal Law 306, 315 (1987) (citing Model Penal Code ง 4.01 cmt., at 166 (1985)) [hereinafter LaFave]. However, if A kills B, thinking that B is an enemy soldier and that the killing is justified as self-defense, then A has the requisite mens rea for murder and could be convicted under the new law but not under the prior law, because he knowingly and intentionally took another's life. Under the amended provision, it does not matter whether A understood that the act was wrong. See Loren R. Roth, Tighten But Do Not Discard JAMA 2947-48 (June 8, 1984) (American Psychiatric Association analyzing mens rea approach to insanity defense); Wallace D. Riley, Reform Not Abolition, JAMA 2949 (June 8, 1984) (American Bar Association analyzing mens rea approach to insanity defense). The new law does away with the traditional affirmative insanity defense that the killing was perceived to be justifiable and therefore done with innocent intent. We will refer to the amended version as the mens rea model. See Harlow M. Huckabee, Avoiding the Insanity Defense Straight Jacket: The Mens Rea Route, 15 Pepp.L.Rev. 1, 25 (1987) [hereinafter Huckabee].

II. Legislative Responsibility

Determining accountability for criminal acts is a serious and difficult task. Government must balance society's interests in order, protection, punishment, and deterrence with the particularly arduous responsibility of caring for the insane and mentally deficient. In formulating an insanity defense, government must carry out the demands of punishment and at the same time assure that those without guilty minds are not unjustly condemned. As one state supreme court justice observed, "In a very real sense, the confinement of the insane is the punishment of the innocent; the release of the insane is the punishment of society." State v. Stacy, 601 S.W.2d 696, 704 (Tenn.1980) (Henry, J., dissenting).

This delicate balancing of public policy is better accomplished in the legislature than in the courts. United States Supreme Court Justice Black, dealing with the nebulous concepts of compulsion and mental disease, stated, "The range of problems created would seem totally beyond our capacity to settle at all, much less to settle wisely, and even the attempt to define these terms and thus to impose constitutional and doctrinal rigidity seems absurd in an area where our understanding is even today so incomplete." Powell v. Texas, 392 U.S. 514, 546, 88 S.Ct. 2145, 2161, 20 L.Ed.2d 1254 (1968) (Black, J., concurring). We made it very clear in Bastian v. King, 661 P.2d 953, 956 (Utah 1983), that "[i]t is the power and responsibility of the Legislature to enact laws to promote the public health, safety, morals and general welfare of society ... and this Court will not substitute our judgment for that of the Legislature with respect to what best serves the public interest." (Citation omitted.) This sound policy of judicial restraint applies all the more when determining the culpability of the mentally ill. "`It is not the function of this Court to evaluate the wisdom or practical necessity of legislative enactments.'" Id. (quoting Redwood Gym v. Salt Lake County Comm'n, 624 P.2d 1138, 1141 (Utah 1981)); see Sullivan v. Scoular Grain Co. of Utah, 853 P.2d 877, 883 (Utah 1993) ("We are not free `to assess the wisdom of a statutory scheme.'" (quoting West Jordan v. Morrison, 656 P.2d 445, 446 (Utah 1982))).

Even if a court finds certain legislation unreasonable or unwise, that alone does not mean it has authority to invalidate it. Regents of Univ. of Mich. v. Ewing, 474 U.S. 214, 226, 106 S.Ct. 507, 514, 88 L.Ed.2d 523 (1985). The law must first rise to the level of violating the constitution before it can be stricken. In this instance, our role is to make such a constitutional evaluation, not to generally critique the legislation.

*363 We emphasize the basic rule of construction that these statutes must be construed, if possible, as being in compliance with both federal and state constitutions. Nelson v. Miller, 25 Utah 2d 277, 282-83, 480 P.2d 467, 471-72 (1971). "`In order to preserve the independence and the integrity of the three branches of government, it is of the utmost importance that the judicial exercise restraint and not intrude into the legislative prerogative.'" Id., 480 P.2d at 472 (quoting Trade Comm'n v. Skaggs Drug Ctrs., Inc., 21 Utah 2d 431, 437, 446 P.2d 958, 962 (1968)). There is no doubt that we cannot strike down any legislation unless it expressly violates the constitution or it is clearly prohibited by "some plain mandate thereof." Id.; Parkinson v. Watson, 4 Utah 2d 191, 197, 291 P.2d 400, 403-04 (1955); see Trade Comm'n, 446 P.2d at 963 (stressing that courts are called upon to state what the law is and not what they think it should be; courts are not the conscience of the people and are not to "express the personal desires or philosophy of its personnel").

III. Federal Due Process Concerns

Defendants argue that the Utah mens rea model violates federal due process because a defendant cannot "rely on insanity as a basis for nonresponsibility for the crime unless he suffers from a form of insanity which serves to negate the mens rea element of the crime." Admittedly, this amended statute limits the insanity defense to a very narrow class of extremely mentally ill defendants. Defendants maintain that since they already have the opportunity to negate the statutorily required mens rea element of a crime and since the State must prove every element beyond a reasonable doubt, the traditional affirmative defense of insanity is no longer available. Its absence, they argue, offends the basic concept of "ordered liberty" protected by the Due Process Clause. See Palko v. Connecticut, 302 U.S. 319, 325-26, 58 S.Ct. 149, 152, 82 L.Ed. 288 (1937), abandoned by Teague v. Lane, 489 U.S. 288, 311-13, 109 S.Ct. 1060, 1075-77, 103 L.Ed.2d 334 (1989). Basically, defendants see Utah's mens rea model as unconstitutional because it would allow them to be convicted even if they did not consciously know the wrongfulness of their actions. As a means to reach their desired conclusion, defendants urge us to establish a combination of the M'Naghten test and the irresistible impulse rule as a minimum requirement of federal due process.^[1]

Only Utah, Idaho, and Montana have limited the insanity defense to negating the mens rea of a crime.^[2] The Supreme Courts of Idaho and Montana have already upheld the insanity defense statutes in those states as constitutional under the federal constitution. State v. Searcy, 118 Idaho 632, 798 P.2d 914 (1990); State v. Korell, 213 Mont. 316, 690 P.2d 992 (1984); see also State v. Byers, 261 Mont. 17, 861 P.2d 860 (1993); State v. Cowan, 260 Mont. 510, 861 P.2d 884 (1993), cert. denied, ___ U.S. ___, 114 S.Ct. 1371, 128 L.Ed.2d 48 (1994). Although the statutes of these three states are not identical, they are very similar. See Idaho Code ง 18-207; Montana Code Ann. งง 46-14-102, -201 to -203, -212 to -213.

In Searcy, the Idaho Supreme Court reviewed the state's insanity defense under both state and federal due process clauses. *364 Defendant Searcy argued that the Idaho law unconstitutionally denied him due process of law because it prevented him from pleading insanity as a defense. The court concluded, "Neither the federal nor the state Constitution[] contains any language setting forth any such right." Searcy, 798 P.2d at 916.

Searcy clarified the actual effect of limiting the insanity defense to negating mens rea. The court explained that only

[t]hree states, Idaho, Montana and Utah, have legislatively chosen to reject mental condition as a separate specific defense to a criminal charge. The statutes in these three states, however, expressly permit evidence of mental illness or disability to be presented at trial, not in support of an independent insanity defense, but rather in order to permit the accused to rebut the state's evidence offered to prove that the defendant had the requisite criminal intent or mens rea....

Id. at 917. We agree with this characterization of the current Utah mens rea model. Although Utah law does not recognize as a defense that defendants did not understand the wrongfulness of their conduct, as would be allowed under an affirmative insanity defense, it still allows them to introduce rebuttal evidence that they lacked the requisite mens rea due to their mental illness.

The United States Supreme Court has never squarely addressed whether due process demands an affirmative insanity defense, id. at 918; neither has that Court articulated a constitutional definition of insanity. Abbott v. Cunningham, 766 F.Supp. 1218, 1223 (D.N.H.1991). However, what little the United States Supreme Court has said suggests that there is no federal due process right to an independent defense of insanity. Searcy, 798 P.2d at 918. In Leland v. Oregon, 343 U.S. 790, 72 S.Ct. 1002, 96 L.Ed. 1302 (1952), the United States Supreme Court upheld an Oregon statute that placed the burden of proving insanity beyond a reasonable doubt on the defendant. The Court declined to adopt any specific insanity test as a requirement under federal due process, concluding that such a holding would be unwarranted given the uncertainty in the psychiatric community, the erratic history of the insanity defense, and the fact that most jurisdictions used a "[k]nowledge of right and wrong" test. Id. at 800, 72 S.Ct. at 1008.

Defendants argue that this means a state is free to choose one test over another but is not permitted under the constitution to reject all of the traditional tests and apply a mens rea model. We cannot accept such a narrow reading of Leland. The very thrust of the Court's holding is that the law does not demand any particular approach to the insanity defense. We read Leland to allow the states some experimentation with various approaches of dealing with the insane criminal defendant. See Byers, 861 P.2d at 866 (noting that United States Supreme Court has determined that Due Process Clause does not require use of any particular insanity defense).

In Powell, 392 U.S. at 535, 88 S.Ct. at 2155, the United States Supreme Court upheld a state law which made it unlawful to be drunk in a public place. In the lead opinion, Justice Marshall set forth the complexities of dealing with personal accountability in the law:

We cannot cast aside the centuries-long evolution of the collection of interlocking and overlapping concepts which the common law has utilized to assess the moral accountability of an individual for his antisocial deeds. The doctrines of actus reus, mens rea, insanity, mistake, justification, and duress have historically provided the tools for a constantly shifting adjustment of the tension between the evolving aims of the criminal law and changing religious, moral, philosophical, and medical views of the nature of man. This process of adjustment has always been thought to be the province of the States.

Id. at 535-36, 88 S.Ct. at 2156. The opinion also echoed the reluctance found in Leland to establish a constitutional right to any particular insanity defense:

But formulating a constitutional rule would reduce, if not eliminate, that fruitful experimentation, and freeze the developing productive dialogue between law and psychiatry into a rigid constitutional mold. It is simply not yet the time to write into the *365 Constitution formulas cast in terms whose meaning, let alone relevance, is not yet clear either to doctors or to lawyers.

Id. at 536-37, 88 S.Ct. at 2156. We agree with these rationales. We are reluctant to embrace any one test, including a combination of M'Naghten and the irresistible impulse test, as the constitutional minimum requirement.

The United States Supreme Court struck down a state statute which allowed continued confinement of one who exhibited antisocial activity but was no longer found mentally ill. Foucha v. Louisiana, 504 U.S. 71, 112 S.Ct. 1780, 118 L.Ed.2d 437 (1992). On an uncontested point, Justice Kennedy acknowledged, "States are free to recognize and define the insanity defense as they see fit." Id. at 96, 112 S.Ct. at 1794 (Kennedy, J., dissenting). In a concurring opinion, Justice O'Connor emphasized that the Court's holding placed no new restriction on the "States' freedom to determine whether and to what extent mental illness should excuse criminal behavior. The Court does not indicate that States must make the insanity defense available." Id. at 88-89, 112 S.Ct. at 1790 (O'Connor, J., concurring); see Ake v. Oklahoma, 470 U.S. 68, 91, 105 S.Ct. 1087, 1100, 84 L.Ed.2d 53 (1985) (Rehnquist, J., dissenting) ("It is highly doubtful that due process requires a State to make available an insanity defense to a criminal defendant.").

Defendants make a historical argument that an affirmative independent insanity defense is so grounded in our legal system that its abolishment offends our fundamental principles of law and justice and therefore violates due process.^[3]Searcy addressed a similar argument and recognized that "[t]he insanity defense has had a long and varied history during its development in the common law." 798 P.2d at 916-17. However, it also recognized that this history has not been uniform and that over the centuries, the implications of a criminal defendant's insanity have changed. Id. at 917. Many different theories have surfaced, been discarded, and resurfaced as humanity has attempted to deal with the elusive concepts of mental illness and guilt. "Not surprisingly, there has resulted a wide disparity in the position taken on this issue both by legislatures and courts in the various states." Id.

For example, although the states have taken two basic approaches to insanity, several variations of different rules exist. A majority of states follow some form of the M'Naghten test; others have adopted variations of the Model Penal Code definition. Six states have added the "irresistible impulse" test, and three states now use the mens rea model. Kathryn J. Fritz, Proposed Federal Insanity Defense: Should the Quality of Mercy Suffer for the Sake of Safety?, 22 Am.Crim.L.Rev. 49, 52-53 (1984); see LaFave, at 310. Never has one approach been constitutionally required or universally deemed the best. Rather, jurisdictions have developed individualized systems that best serve their own public policies.

Although Utah has adopted a minority position, its approach has been endorsed by credible branches in the scientific and medical fields. In 1983, the American Medical Association approved a report by its Board of Trustees recommending adoption of the mens rea model. Committee Report, Insanity Defense in Criminal Trials and Limitation of Psychiatric Testimony, JAMA 2967 (June 8, 1984) (making an adamant argument in support of this position) [hereinafter AMA Report]. "Thus, [the mens rea model] is now the policy of the American Medical Association, as well as the concept adopted in Idaho, Montana, and Utah." Huckabee, at 26-27.

The Montana high court has also determined that there is no constitutional right to have an independent insanity defense. Korell, 690 P.2d at 996. There, the court responded to the historical argument as follows: "We reject appellant's contention that from the earliest period of the common law, insanity has been recognized as a defense. What we recognize is that one who lacks the requisite criminal state of mind may not be *366 convicted or punished." Id. at 999.^[4] Utah's mens rea model provides this minimum standard of protection to defendants. We agree with Korell that the common law and our basic principles of ordered liberty are not offended by the mens rea model. See also Cowan, 861 P.2d at 888 (holding that the Due Process Clause does not require the use of any particular insanity test or allocation of burden of proof).

Defendants rely upon three dated state decisions which struck down their respective state statutes as unconstitutional because they abolished the insanity defense completely. State v. Lange, 168 La. 958, 123 So. 639 (1929); Sinclair v. State, 161 Miss. 142, 132 So. 581 (1931); State v. Strasburg, 60 Wash. 106, 110 P. 1020 (1910). These cases are distinguishable because they involved "statutes which precluded any trial testimony of mental condition, including trial testimony which would have rebutted the state's evidence of the defendant's state of mind." Searcy, 798 P.2d at 919 n. 6. Utah's law does not do this. Rather, it allows defendants to present evidence of mental illness to specifically negate the required state of mind.

Determining whether a law is wise public policy and determining whether it is constitutional are two separate matters. It is appropriate for this court to decide only the latter, and in light of the foregoing discussion, we conclude that the current Utah insanity defense does not violate federal due process.

IV. State Due Process Concerns

Defendants next contend that Utah's statutory scheme violates due process under the state constitution. Utah Const. art. I, ง 7 ("No person shall be deprived of life, liberty or property, without due process of law.").

Defendants provide a detailed history of how Utah has been a pioneer in the treatment of the insane and mentally ill. From its territorial days to 1983, Utah has demonstrated extraordinary compassion and insight in dealing with this class of society. Salt Lake City had the first institution for the mentally ill in the western United States. Charles R. McKell, History of the Utah State Hospital, Provo (1948) (unpublished Master's thesis, University of Utah). Territorial law made it a misdemeanor to harshly treat or neglect any insane person. 1876 Utah Laws ch. XI, ง 193. Throughout most of its history, Utah had one of the most liberal statutory approaches governing the culpability of those with mental illness. State v. Kirkham, 7 Utah 2d 108, 111, 319 P.2d 859, 861 (1958). Because of this unique history, defendants assert that the state due process protection exceeds that of its federal counterpart, at least as far as the insanity defense is concerned. Defendants argue, therefore, that the state due process clause prohibits abolishment of the traditional affirmative insanity defense. We disagree.

Defendants' reliance upon this history is misplaced. It is one thing to demonstrate that Utah has a unique background in dealing with mental illness; it is quite another to conclude that state due process must comply with this background and that any legislation that abandons Utah's historical practices violates the constitution. The legislature is allowed to reform the penal law; it is not locked into the past. As the State explains in its brief, "[D]efendant [does not] have a vested right to a defense simply because it was previously available." See State v. Padilla, 776 P.2d 1329, 1331 (Utah 1989) (stating that a similar argument relying on outdated criminal law was frivolous).

In any event, Utah's history has not been a model of consistency in the area of the insanity defense. The state has employed different approaches at different times over the past one hundred years. The irresistible impulse test, for example, was initially rejected, State v. Mewhinney, 43 Utah 135, 149, 134 P. 632, 638 (1913), was later recognized, *367 State v. Green, 78 Utah 580, 602, 6 P.2d 177, 185 (1931), and was then rejected again. State v. Sessions, 645 P.2d 643, 645 (Utah 1982). Utah has sampled several variations over the years, demonstrating the somewhat erratic nature of the relationship between criminal culpability and insanity.

Defendants also rely upon past decisions of this court to support their state due process argument. See, e.g., Mewhinney, 134 P. at 638 (implementing insanity test requiring defendant to recognize wrongfulness of conduct); State v. Brown, 36 Utah 46, 102 P. 641 (1909) (recognizing that an individual could have the necessary mens rea but not be criminally culpable due to insanity). These cases are distinguishable. This court decided them prior to 1983, when the legislature limited the insanity defense. These former decisions either interpreted a different statutory standard that existed at that time or simply expressed a judicial preference for one test over another. None of the cases are grounded in the Utah constitution, and they are not binding today in light of section 76-2-305. See Korell, 690 P.2d at 999-1000.

The Utah legislature has made a policy decision to limit the traditional insanity defense. We hold that this policy decision, though limiting for defendants, does not violate their state due process rights.

Although the legislature has limited the insanity defense, it has provided the guilty and mentally ill verdict as an option. "A judgment of guilty and mentally ill does not serve to exonerate or excuse the defendant; rather, the offender found guilty and mentally ill is held accountable for his criminal conduct, yet because of his mental illness, may need specialized treatment." State v. DePlonty, 749 P.2d 621, 626 (Utah 1987).

"Guilty and mentally ill" is a deliberate variation of the "guilty but mentally ill" provision adopted by some states. The [Utah] legislative committee thought that the words "guilty but mentally ill" implied a causal connection between the mental illness and the crime. That implied connection, however, is inappropriate under the Utah statute because "guilty and mentally ill" focuses on the defendant's state of mind at the time of sentencing, regardless of his state of mind at the time of the crime.

Young, 853 P.2d at 384 (quoting Utah Legislative Survey โ€” 1983, 1984 Utah L.Rev. 115, 156 n. 265); see Utah Code Ann. งง 77-16a-103, -104. If a defendant is found not guilty by reason of insanity, he is acquitted of all criminal culpability. However, he is subject to civil confinement. If a defendant is found guilty and mentally ill, the trial court first conducts a hearing to "determine the defendant's present mental state." ง 77-16a-104(1). If the court "finds by clear and convincing evidence that the defendant is currently mentally ill," it may sentence the defendant just as any other guilty defendant and (1) commit him to the state hospital, (2) order probation, or (3) order him to the custody of the Department of Corrections. ง 77-16a-104(3). If a defendant is committed to the state hospital for confinement and treatment, he remains there for eighteen months or until he reaches "maximum benefit." ง 77-16a-202(1)(b).

The guilty and mentally ill verdict buffers some of the harsher consequences of eliminating an independent insanity defense. It affords the trial judge discretion in determining whether one found guilty and mentally ill should receive medical attention rather than traditional incarceration. This new verdict option acknowledges that a defendant can be both guilty and mentally ill, and it aids the jury in resolving the dilemma of whether to acquit due to insanity. The verdict provides a middle ground between "guilty" and "not guilty by reason of insanity." It allows for "special disposition of mentally ill offenders to a custodial or therapeutic setting for the purpose of treating the mental illness." Utah Legislative Survey โ€” 1983, 1984 Utah L.Rev. at 156-57.

Defendants argue that Utah's approach has thrown hundreds of years of development out the door. Existence of the guilty and mentally ill verdict contradicts such assertions. We believe that the mens rea model coupled with this inventive verdict is a constitutionally valid system of dealing with an ever-adapting field. The new law is not a digression to ages of ignorance and fear of mental illness, but a legitimate approach to *368 dealing with the sometimes baffling relationship between insanity and mens rea. See AMA Report, at 2976 (concluding that mens rea approach surpasses, both legally and morally, all traditional insanity defenses while it leads to "a more realistic appreciation of the relationship between mental impairment and criminal behavior").

V. Burden of Proof

For defendants to be convicted, due process mandates that the prosecution prove every element of the charged crimes beyond a reasonable doubt. In re Winship, 397 U.S. 358, 364, 90 S.Ct. 1068, 1072, 25 L.Ed.2d 368 (1970); State v. Swenson, 838 P.2d 1136, 1138 (Utah 1992). Defendants assert that the Utah insanity defense scheme unconstitutionally relieves the prosecution of this burden in violation of due process.^[5] They contend that since section 76-2-305 allows them to rely on insanity only to negate the required intent, an element of the crime, in essence they are forced to prove that they lacked the requisite mens rea rather than the prosecution proving that they possess it. If true, this would shift the burden of proof.

This theory has previously been considered and rejected. In Byers, 861 P.2d at 864-65, the court explained that the mens rea model enables a defendant to present evidence supporting his insanity claim but does not require the defendant to prove beyond a reasonable doubt that his disease negates the requisite intent. "When a burden `shifts' it goes from one party to another, from prosecution to defendant. But the prosecution here was not relieved of its burden. The jury was not instructed that [the defendant] had any kind of burden at all." Id. at 865; State v. Beam, 109 Idaho 616, 710 P.2d 526, 531 (1985).

Section 76-2-305 does not shift any burden of proof. It merely enables defendants to present evidence that rebuts the State's case against them. From beginning to end, the prosecution carries the responsibility of proving each and every element of the crime beyond a reasonable doubt.

VI. Arbitrary and Capricious and Equal Protection

The next issue to address is whether section 76-2-305 is arbitrary and capricious and therefore violative of state due process, Utah Const. art. I, ง 7, or federal and state equal protection, U.S. Const. amend. XIV, Utah Const. art. I, ง 24. Both the federal and state constitutions require that similarly situated individuals be treated alike under the law unless there is a reasonable basis for treating them differently. Greenwood v. City of North Salt Lake, 817 P.2d 816, 821 (Utah 1991); Malan v. Lewis, 693 P.2d 661, 670 (Utah 1984). Defendants argue that Utah's mens rea model illegally differentiates between mentally ill defendants solely on the content of their delusions. One insane defendant may kill under the severe delusion that he is killing something that is not human. Another may kill under a delusion that he is being attacked and that his actions are justified as self-defense. The first is found not guilty by reason of insanity under the mens rea model, while the second may be convicted. According to defendants, each is equally mentally ill, but they are treated differently because some "clinically indistinguishable delusional system" causes them to have different hallucinations.

We find that there is a reasonable basis for this difference and that the mens rea model is not arbitrary and capricious.^[6] The legislature has drawn a line between those who do not comprehend that they are *369 taking a human life and those who do. The offenders in the first group do not know that they are hurting or killing another person, while those in the second group do know. The first group makes no moral judgment, while the second group realizes that they are actually killing someone and therefore their actions come closer to the realm of criminality. See AMA Report, at 2975 ("[T]he law must first discard the notion that insanity short of that which negates mens rea absolves a defendant of moral and legal responsibility for his acts."); see also State v. Neely, 112 N.M. 702<