Negating Mens Rea

Negating Mens Rea

The insanity defense answers a question that arises only after the prosecution has proved its case. Even if the defendant committed the act with the required state of mind, does mental disease excuse the defendant from criminal responsibility? The Model Penal Code makes that an affirmative defense, which the defendant must raise and for which the law sets a burden.¹ Mental-disease evidence can also be offered for an earlier question: whether the prosecution has proved the state of mind the offense itself requires, such as purpose or knowledge. On that track the evidence works as ordinary proof about an element, offered to show that the prosecution's case on the mental element falls short, and nothing is being excused.

The reason for treating the evidence this way comes from how the prosecution proves mens rea. A defendant's state of mind cannot be observed directly, so the prosecution usually proves it by inference from outward conduct, and a shooting that looks deliberate invites the conclusion that the shooter meant to kill. Mental disease can break that inference, because a disorder that distorts perception or judgment bears on what the defendant actually perceived and intended when acting. If the prosecution must prove the mental element beyond a reasonable doubt, evidence that makes the element more or less likely should come in under the same rules as any other relevant evidence. Excluding it would leave the factfinder to decide the element with the most informative explanation of the defendant's mind withheld, and the appearance created by conduct alone would carry the burden of proof.

This section develops that idea in two steps. The first sub-section states the Code's evidence rule, which admits mental-disease evidence whenever it is relevant to whether the defendant had a required state of mind. The second sets out the due process argument that a defendant has a constitutional entitlement to contest mens rea with such evidence, and why a categorical exclusion is troubling. That argument does not settle the matter by itself. The section on Clark v. Arizona that follows shows how far it carries when a state confines this evidence to the insanity defense.

MPC Rule of Evidence

The Model Penal Code states the evidence track in a single sentence. Section 4.02(1) makes evidence that the defendant suffered from a mental disease or defect admissible whenever it is relevant to prove that the defendant did or did not have a state of mind which is an element of the offense.² The provision works as an evidence rule for mental state, and it creates no defense. A defense such as insanity asks the factfinder to excuse a defendant after the prosecution has already proved the offense, and the Code makes that an affirmative defense with its own burden.³ Section 4.02(1) asks a different question, which is whether the testimony helps the jury decide an element the prosecution must prove. The prosecution's burden to prove the mental state beyond a reasonable doubt therefore stays exactly where it was, even when the defendant offers expert testimony.⁴

The reason for the rule follows from what a mental element is. Purpose, knowledge, premeditation, and the other states of mind that offenses require are facts the prosecution must prove, and the evidence that bears on them does not change character because a psychiatrist supplies it. The Code's drafters reasoned that if the law gives states of mind legal significance, psychiatric evidence should be admissible to prove or disprove them to the same extent as any other relevant evidence.⁵ Excluding it would leave a category of defendants whose mental state could not be contested, and an offense that specifically requires a bad state of mind would operate as a strict liability offense against abnormal defendants.⁶ The public-safety worry that a successful challenge could free a dangerous person is met by involuntary civil commitment, which does not depend on a conviction.⁷ Critics point to practical risks, such as jury confusion and expert opinions tailored to whichever side retained the expert, and the usual response is careful screening by the trial judge, who can require a proffer outside the jury's presence.⁸

Two features of the text carry most of the rule's reach. The first is that the evidence may show that the defendant did have a required state of mind as well as that the defendant did not, so either side may offer it, and a prosecutor who wants to show that a disorder left the defendant fully able to plan and intend may use the same kind of testimony.⁹ The second is that the evidence must bear on a state of mind that is an element of the charged offense, which makes relevance to that element the test and leaves the diagnosis as a starting point only.¹⁰ Jurisdictions also differ on the form of the expert's opinion. In most, the expert states whether the defendant, because of the disability, did or did not have the mental state of the offense; in others, the expert addresses whether the defendant had the capacity to form it, and in either form the prosecution must still prove the mens rea beyond a reasonable doubt.¹¹

Two decided cases show the two forms. In Sandstrom v. Montana the defendant admitted the killing but argued that a personality disorder aggravated by alcohol meant he did not act purposely or knowingly, and two court-appointed mental health experts described his mental state at the time.¹² He had first filed notice of an insanity defense and withdrew it at trial, contending that he remained able to form the required intent but did not have it at the time of the killing.¹³ The expert evidence therefore addressed his actual state of mind, with no claim of excuse. The trial in Leland v. Oregon shows the capacity form: the judge told the jury to weigh the insanity evidence together with all other evidence on the defendant's ability to premeditate, form a purpose, deliberate, and act willfully and maliciously, whether or not the jury found him insane.¹⁴ The Court recognized that a jury could find the defendant mentally incapable of the premeditation and deliberation that first degree murder required and yet not find him legally insane, which is the space the evidence rule occupies.¹⁵

The logic of relevance is easiest to see in a theft or fraud prosecution. A defendant with bipolar disorder who becomes exhilarated and excited during a manic phase pays for a large clothing purchase with a worthless check, and a psychiatrist is prepared to testify that the condition led the defendant to believe the money was in the account or could be deposited in time to cover the check.¹⁶ Fraud and theft require a culpable mental state about the check, and a sincere belief that it was good bears directly on that state. The testimony is therefore relevant to an element and the rule admits it, whatever the jury ultimately makes of it.

A second textbook illustration tracks the facts of Clark v. Arizona, where a defendant with paranoid schizophrenia offered testimony that he did not recognize that he was shooting a police officer rather than an alien disguised as one.¹⁷ In the illustration, Hector, who has paranoid schizophrenia, shoots a uniformed officer who has come to his door in a patrol car with its lights flashing after a neighbor complained about extremely loud music, and he is charged with intentionally killing a police officer in the line of duty. A psychiatrist would testify that Hector was out of touch with reality, believed the victim was an alien disguised as an officer, and, like others with the illness, may have played music loudly to drown out threatening voices he heard. The prosecutor would answer with a witness who heard Hector say he wanted to kill police officers and with the theory that the music was bait.¹⁸ The expert opinion tells the jury what Hector perceived and meant, so it is relevant to whether he intended to kill an officer, and the jury weighs it against the prosecution's account. Whether the Constitution requires that result, or lets a state confine the testimony to insanity, is the question the following sections take up.

When the evidence succeeds, the result differs from the insanity track. A jury with reasonable doubt on the mental element does not return a verdict of not guilty by reason of insanity, and no commitment follows from that finding; it concludes that the prosecution has not proved the element, which means acquittal of the charge that requires it, with conviction of a lesser offense usually still possible.¹⁹ The most common concrete result is a murder case in which evidence of mental illness shows the defendant did not premeditate and deliberate, reducing first degree murder to second degree.²⁰ Because the two tracks are separate, steps required only to preserve an insanity defense, such as advance notice or a special plea, do not bar this evidence, and in a bifurcated trial it is admissible at the first stage of the trial and only the first stage.²¹ The defendant bears a burden of producing the evidence, while the prosecution keeps the burden of proving mens rea beyond a reasonable doubt.²²

Relevance to the element is the filter, and Texas decisions applying an evidence-rule approach show where it bites. In Williams v. State a Texas court explained that Texas does not recognize diminished capacity as an affirmative defense and treats it as a failure of proof, so lay and expert testimony of mental disease or defect is admissible when it directly rebuts the particular mens rea the charged offense requires, unless a specific evidentiary rule excludes it.²³ In Ruffin, the defendant shot at ten police officers during an armed standoff and was charged with an offense requiring intent to shoot a police officer; his expert would have testified that delusions led him to believe he was shooting at Muslims, and the court held the testimony clearly relevant to intent and reversed.²⁴ In Jackson, a defendant with paranoid schizophrenia and bipolar disorder killed his brother, and testimony that paranoia made him think the brother was out to get him supplied an excuse for a killing he knew he was committing and did not negate the intent to kill.²⁵ Mays reached the same result for paranoid ideation, because the defense expert conceded that paranoia does not prevent a person from acting intentionally or knowingly, so the evidence went to motive.²⁶ The line between Ruffin and Jackson is what the delusion changed: in Ruffin it altered what the defendant believed he was aiming at, which is an element, and in Jackson it supplied a reason for an act whose nature he understood. Examinees lose this issue when they treat a diagnosis alone as relevance.

The same section of the Code also contains a bracketed second subsection on capital sentencing, which a later section of this chapter takes up.²⁷ Everything above concerns the first subsection only. The next section gives the constitutional argument that a defendant may contest mens rea with such evidence, and the section after it turns to Clark v. Arizona, where a state confined the evidence to the insanity defense.

Due Process Argument for Admission

The evidence rule in § 4.02(1) reflects a choice by the Code's drafters, so a jurisdiction that has not adopted it can still be asked whether the Constitution demands the same result. The argument that it does begins with the reasonable-doubt standard. The State must prove every ingredient of an offense beyond a reasonable doubt, and it may not relieve itself of that burden by presuming an element once it has proved the others.²⁹ A legislature decides which elements an offense contains, but as the dissent in Montana v. Egelhoff put it, once the legislature writes a purpose or knowledge requirement into the definition, the defendant has the right to insist that the State prove it.³⁰ What remains is whether the defendant must be permitted to contest that element. The argument for admission answers yes, because a burden of proof means little if the defense is forbidden to test the prosecution's account of what the defendant had in mind.

The mechanism is easy to trace. A mental state is usually proved circumstantially, by inference from what the defendant did and said, so the jury's picture of the defendant's mind comes from outward conduct unless someone supplies another explanation. If the jury may not consider the defendant's evidence about the disorder behind that conduct, it may impute to the defendant a mental state the defendant did not have, and the prosecution's task becomes correspondingly easier.³¹ Reasonable doubt also arises from defense evidence that casts doubt on what had seemed certain, and a rule that denies the defendant any chance to offer reliable, relevant impairment evidence lowers the burden the State was supposed to carry.³² Those points support a strong argument that a defendant has a constitutional right to use mental-illness evidence relevant to mens rea.³³ Egelhoff shows that the argument is contested: the statute there barred jury consideration of voluntary intoxication on mental-state elements, and the Court's judgment reversed the state high court's holding that the statute violated due process.³⁴

A state high court applied the argument to a statute that allowed evidence of an impaired mental condition only where specific intent was an element of the offense. The defendant was charged with third degree assault, which required knowledge or recklessness, and offered evidence of adult minimal brain dysfunction to show that the required mental state was absent. The trial court read the statute to bar all mental-impairment evidence in nonspecific-intent prosecutions and excluded it.³⁵ The high court held that the exclusion violated due process, because forbidding the defendant to contest an element the prosecution must prove assumes all the features of an impermissible presumption of culpability and makes the prosecution's evidence uncontestable as a matter of law. It concluded that reliable and relevant impairment evidence is admissible, on a proper foundation, to negate the culpability element, and it noted that this holding conforms to § 4.02(1).³⁶

The comparison to a presumption has support in Sandstrom v. Montana, where the defense on intent rested on mental-health testimony that the defendant did not act purposely or knowingly, and the trial court told the jury that the law presumes a person intends the ordinary consequences of voluntary acts.³⁷ A reasonable juror could have treated that instruction as mandatory, and the Court would not save the conviction on the theory that the jury might have found knowledge by some other route, since a general verdict does not reveal which route it took.³⁸ A presumption of intent takes the contest over mens rea away from the defense by instruction, and an exclusion rule takes it away by removing the defense's evidence. Under either device the jury decides the element without a fair test of the prosecution's inference.

The State's most natural reply is that the insanity defense already gives a mentally disordered defendant a way to be heard, so no door has been closed. The state high court rejected that reply because legal insanity and mens rea answer different questions. Insanity excuses a defendant whose mental disease leaves the defendant without the capacity to distinguish right from wrong or to conform to the law, while the mens rea inquiry asks what state of mind the defendant in fact had. The prosecution's burden on the charged mental state is therefore no less where the defendant has been found legally sane, and confining the defendant to the insanity defense as the only way to contest the mental element would amount to a conclusive presumption of culpability.³⁹ Examinees lose this issue when they treat a finding of legal sanity as proof of the charged mental state.

The presumption of sanity explains how the two tracks fit together. It spares the prosecution from alleging, as an element of every charge, that the defendant had the capacity to form mens rea, and it can be put in issue in two places: through mental-disease evidence offered against the prosecution's burden to show mens rea, and through an insanity defense, which tests whether a mental difference is strong enough to excuse a defendant even after the prosecution has proved every element.⁴⁰ The second place carries a burden a State may assign to the defendant, because an affirmative defense that does not negate an element need not be disproved by the government. Once the elements have been proved on all the evidence, including evidence of the defendant's mental state, a State may refuse to sustain insanity unless the defendant demonstrates it by a preponderance of the evidence.⁴¹ Mens rea evidence carries no such shift in the burden of persuasion, because it bears on an element the prosecution must prove.

The right to present this evidence is real, but it has limits, and those limits shape the next section. In Clark v. Arizona the Court accepted that a defendant has a due process right to present favorable evidence on an element that must be proved, and that evidence of mental disease and incapacity is relevant to rebut proof that the defendant formed the required mens rea.⁴² The Court added that the right to introduce relevant evidence can be curtailed for good reason, such as unfair prejudice, confusion of the issues, or the potential to mislead the jury, and that if evidence may be kept out entirely, its consideration may be restricted, for example by channeling it to the insanity defense.⁴³ The question then becomes whether the reasons for the restriction satisfy fundamental fairness. State courts apply the same boundary in everyday rulings. In Williams v. State a Texas appellate court faced a claim that excluding expert testimony on mental illness violated the due process right to present a defense, and it reviewed the exclusion for abuse of discretion and framed the inquiry around whether the testimony did more than excuse the intent, meaning whether it showed the defendant was prevented from forming it.⁴⁴

How far the argument carries when a state does not exclude the evidence outright but channels it to the insanity defense is the question the next section takes up through Clark.