Estimated reading time: 9 minutes
Key Takeaways
- The insanity defense in Minnesota relies on Rule 20 and the M’Naghten standard, which defines when mental illness is a factor in legal responsibility.
- A defendant can be excused from criminal liability if their actions stem from mental illness, but diminished capacity is not recognized as a valid defense in Minnesota.
- Competency to stand trial pertains to a defendant’s current mental state and can often be restored with medication, while the insanity defense focuses on the defendant’s mental state at the time of the offense.
- Rule 20 examinations assess both competency and insanity, influencing whether a trial occurs and how cases are handled in court.
- Social stigma affects how individuals with mental illness engage with the justice system, often discouraging them from asserting an insanity defense.
Criminal defense attorneys can make sure that the court is aware of mental illness defenses, including the insanity defense, that might excuse a defendant’s otherwise criminal conduct. And other, additional mental health issues come up in criminal cases, including Rule 20. Let’s explore them.
What is “Rule 20” in Minnesota? Mental Illness can be a defense in Minnesota criminal cases in at least two ways. The M’Naghten insanity defense is the first:
“Because of mental illness or cognitive impairment, the defendant, at the time of committing the alleged criminal act, was laboring under such a defect of reason as not to know the nature of the act or that it was wrong.”
Rule 20.02, Minn. Rules of Crim. Pro.
Insanity Defense & Mental Health
Rule 20 of the Minnesota Rules of Criminal Procedure addresses mental health defenses. These issues come up for every offense level: felonies, gross misdemeanors, and misdemeanors.
Outdated insanity defense: The M’Naghten rule, insanity defense comes from the 1843 English M’Naghten case involving a paranoid schizophrenic. Should we update it to reflect modern scientific understanding of mental illness? The Model Penal Code suggests an update.
It is an affirmative defense. That means the defense has the initial burden of asserting the insanity defense, and producing some evidence to support it. And then, the burden shifts to the government. So then, the prosecutor attempts to prove the defendant criminally responsible, despite mental illness.
Excuse defense
Some characterize the insanity defense as an excuse defense (as opposed to a justification defense). The defendant did the prohibited act intentionally but criminal responsibility is excused, because the act was the product of a diseased mind. Minnesota has codified the defense in Minnesota Statutes § 611.026:
“No person having a mental illness or cognitive impairment so as to be incapable of understanding the proceedings or making a defense shall be tried, sentenced, or punished for any crime; but the person shall not be excused from criminal liability except upon proof that at the time of committing the alleged criminal act the person was laboring under such a defect of reason, from one of these causes, as not to know the nature of the act, or that it was wrong.”
Minn. Stat. § 611.026
Note the “or cognitive impairment” language and compare with the defense of extreme intoxication (vs. involuntary intoxication.)
Medication can restore Competency
The second way mental health is a “Rule 20” issue in a Minnesota criminal case is the defendant’s Competency. A defendant is incompetent to participate if lacking the ability to:
- rationally consult with legal counsel,
- understand the proceedings, or
- participate in the defense,
- due to mental illness, deficiency or other disability.
A defendant who is incompetent due to mental illness can often regain competency with anti-psychotic medications.
Rule 20, Rules of Criminal Procedure: Rule 20.02 of the Minnesota Court Rules of Criminal Procedure addresses the insanity defense; while Rule 20.01 addresses mental competency.
And Minnesota Statutes § 611.026 is the Minnesota version of the M’Naghten insanity defense standard, while Minnesota Statutes §§ 611.40 through 611.59 lay out procedures for competency proceedings.
Symptoms: active or in remission?
The time period of the mental illness can be important. The insanity defense is concerned with “at the time of committing the act.” But, in contrast, competency to participate in legal proceedings relates to the defendant at the time of the legal proceedings.
A person can treat and alleviate their mental illness symptoms with psychiatric medications. It can take weeks, however, for the medications to reach a therapeutic level. Also, psychiatric physicians need time to find an effective medication for a patient.
Reconstructing past events based on available evidence, is challenging but necessary. The insanity defense depends upon the defendant’s mental heath at the time of the alleged offense. The defendant’s current mental health does not matter.
But competency is all about now. Competency to participate in present and future court proceedings can often be restored with medications. But this is not always true, for example in the case of severe Traumatic Brain Injury (TBI) or cognitive loss.
Mental Health issues come up in people’s lives and in criminal cases in other ways as well. Whether or not an accused person met the ancient standard of the M’Naghten rule; the person may have also have had diminished capacity.
Diminished capacity defense in Minnesota
Minnesota does not recognize “diminished capacity” due to mental illness, as a defense to criminal liability. See, Cuypers v. State, 711 NW2d 100, 105 (Minn. Supreme Court 2006).
“Existing law presumes that during any trial, “defendant[s] standing trial, are responsible for their acts, i.e., that they have the capacity to intend what they do.” State v. Bouwman, 328 N.W.2d 703, 705 (Minn.1982). “The law recognizes no degree of sanity. Applying socially and morally acceptable standards a line has been drawn — on one side are the legally sane, on the other side are the legally insane.” Minnesota does not recognize the doctrine of diminished capacity or diminished responsibility. See State v. Provost, 490 N.W.2d 93, 100 (Minn. 1992).”
State v. Anderson, 789 NW2d 227 (Minn. Supreme Court 2010)
So, courts will generally not allow psychological evidence going to the issue of the defendant’s capacity to form the intent to do the prohibited act. Contrast that with cases where the defendant may present evidence supporting a mental illness “excuse” defense, and presents psychological evidence in the second phase of a bifurcated trial going to the issue of whether defendant should be “excused from criminal liability except upon proof that at the time of committing the alleged criminal act the person was laboring under such a defect of reason, from one of these causes, as not to know the nature of the act, or that it was wrong.” See, Minnesota Statutes § 611.026, and Rule 20.02, Minnesota Rules of Criminal Procedure.
Diminished capacity evidence at sentencing:
“It is clear from the record that defendant, ‘because of * * * mental impairment, lacked substantial capacity for judgment when the offense was committed.” Minnesota Sentencing Guidelines and Commentary, II.D.2.a.(3).”
State v. Wall, 343 NW2d 22 (Minn. Supreme Court 1984)
In Minnesota, then, courts generally do not admit “diminished capacity” evidence at trial on the issue of the defendant’s intent (intent element of prosecutor’s prima facie case); but do admit evidence of the mental illness relevant to the M’Naghten insanity defense (See, Rule 20.02 and Minnesota Statutes § 611.026).
At sentencing, however, Minnesota law does recognize diminished capacity (“lacked substantial capacity for judgment”) as a mitigating factor.
Civil vs. Criminal Commitment
When a court “commits” person, the person loses their civil rights, including their liberty. The judge transfers them to the custody, care and control of the head of the prison (criminal), or of a state hospital (civil).
If the legal basis for the commitment is mental illness under Minnesota Statutes Chapter 253B; then the result is a Civil Commitment Order.
But if the commitment is for a criminal sentence then the result is a Criminal Commitment Order. A criminal court commits the person to the care and custody of the Commissioner of Corrections.
Civil Commitment legal process
The civil commitment process in Minnesota can involve medical issues other than mental health. These include chemical dependency, withdrawal-induced psychosis, developmental disability, traumatic brain injury, dementia and other issues.
The court’s civil commitment process connects with the both the insanity defense and a competency defense in a criminal case. For example, under Rule 20.01 of the Minnesota Rules of Criminal Procedure,
Subd. 6. Procedure After Competency Proceedings.
Rule 20.01, Minn. Rules of Criminal Procedure
“(b) (1) Finding of Mental Illness. … If the defendant is not under commitment, the court must commence a civil commitment proceeding. The court must supervise the commitment as provided in Rule 20.01, subd. 7.”
And, under Rule 20.02,
“Subd. 8. Effect of Not Guilty by Reason of Mental Illness or Deficiency.
Rule 20.02, Minn. Rules of Criminal Procedure
(1) Mental Illness. When a defendant is found not guilty by reason of mental illness, and … the defendant is not under commitment, the court must commence a civil commitment proceeding and order the defendant to be detained in a state hospital or other facility pending completion of the proceedings. In felony and gross misdemeanor cases, the court must supervise the commitment as provided in Rule 20.02, subd. 8(4).”
Rule 20 Exam: insanity defense vs. competency
When defense counsel, the prosecutor, or the judge perceive mental health issues, the court can order a Rule 20 examination by a court examiner (e.g., psychologist). This can happen at any stage in the court process.
The Rule 20 examination is a psychological or psychiatric assessment. The examiner will develop an expert opinion on Competency under Rule 20.01, or on an insanity defense under Rule 20.02. The court will appoint a Rule 20 Examiner who is the court’s expert.
The defense has the right to retain another expert to develop an independent opinion on either or both issues. Eventually the judge may hold a hearing and rule on Competency or make initial determinations on a 20.02 insanity defense. The insanity defense may ultimately go to a jury.
The common, major mental illnesses are mood disorders (e.g., bipolar disorder) and thought disorders (e.g., schizophrenia).
Mental health issues can also influence a court’s judgment about an appropriate sentence.

Social stigma & insanity defenses
Stories in movies show mentally ill people as dangerous, or using mental illness as a trick to escape criminal responsibility. But such story clichés mislead.
In reality, people with mental illness are not more likely to be perpetrators of crime than other people; but are more vulnerable to victimization. And, perhaps due to stigma. people with mental illness often refuse to assert a mental illness or insanity defense even when obvious to others. Attorney Thomas Gallagher has been instructed by clients not to raise a mental illness defense despite strong evidence for it. His view is the attorney should respect client wishes in this situation.
Insanity defense: Bifurcated trial
If the defendant is competent, she has the right to a jury trial. If she makes an insanity defense; the jury decides whether she was not guilty by reason of insanity at the time. But the court will conduct the trial in two parts; bifurcates the trial.
In part one, the prosecutor will attempt to prove all of the elements of the crimes claimed, including criminal intent. If the jury concludes the defendant is guilty beyond doubt; then a second part to the trial begins.
In part two, the defense attorney brings evidence that the defendant is not-guilty by reason of insanity, at the time. The prosecutor has the burden of proving beyond doubt that the defendant is criminally responsible despite their insanity. Then the jury deliberates again on this issue.
The jury verdict in part two could be guilty or not-guilty by reason of insanity. If the verdict is “not-guilty by reason of insanity,” the judge will begin civil commitment proceedings.
Attorney Thomas Gallagher’s experience
Thomas Gallagher completed his undergraduate degree major at one of the best Psychology Departments, at the University of Minnesota. This included coursework in Abnormal Psychology, Experimental Psychology, Behavioral and Cognitive Psychology, Social Psychology, Perception, Linguistics, Developmental (Child) Psychology, Statistics, and Industrial Psychology.
And Thomas Gallagher’s experience includes:
- volunteer with Youth Emergency Service Hotline and Referral,
- Sociology Research Assistant, on a Gender and Sentencing Study,
- Teacher-Therapist, with Minneapolis Children’s Hospital summer program for Exceptional Children,
- intern for a major foundation studying non-profit Grantee Evaluation.
Since then, Thomas Gallagher has been a life-learner and student of Psychology, as well as Psychology and the Law. See: The Psychology of Juries < Book Review
For 13 years Gallagher was a panel lawyer in Hennepin County defending persons under Petition for Civil Commitment as Mentally Ill or Chemically Dependent.
During that time, he visited every psychiatric hospital ward and detox center in the Twin Cities, and many beyond.
Thomas Gallagher uses the latest version of The Diagnostic and Statistical Manual of Mental Disorders (DSM), published by the American Psychiatric Association. He uses DSM-5 as an aid in understanding cases and best representing clients.
Question? Call Lawyer Thomas Gallagher, 612 333-1500
Attorney Thomas Gallagher raises the insanity defense and mental health issues for clients in criminal cases. He’s done so many times, over his 38 years of practice.
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