Criminal Law

Class Info

Law School: Liberty University School of Law

Course ID: LAW 535

Term: Fall 2018

Instructor: Prof. Tchividjian

My Grade Earned: C+

Books Used
  • Criminal Law: Doctrine, Application, and Practice by Jens David Ohlin

For a crime to be committed, it requires both a guilty act and a guilty mind.

Actus Reus

Actus reus, or a "guilty act," is the physical act that is required for a crime to have been committed.

It is generally considered implicitly implied that the acts must be voluntary—done by a willed bodily movement.

Possession

Possession usually requires the defendant's to procuring, receiving, or failing to dispose of the property to be the voluntary act.

Possession can also be constructive if one has power over an item, even if he has no physically possessed it. This requires him to have:

  1. knowledge of the property,
  2. the ability to control the property, and
  3. intent to exert control over the property.
Omission

Omissions are the opposite of acts; they are the failure to act. Generally, an omission cannot be a crime, but in some circumstances, not acting can satisfy the requirement of actus reus.

A conviction can only be based on an omission when the defendant had a legal duty to act.

Bystander

Bystanders usually fall under the general rule of omissions and are not liable for failing to stop a crime. Exceptions may exist if a bystander has a legal duty to act, as in an omission, or if the bystander "encouraged" the crime and thereby became an accomplice.

Mens Rea

Mens rea, or a "guilty mind," is the culpable mental state that is required for a crime to have been committed.

Some crimes called strict liability offenses do not require mens rea to be convicted thereof.

The Model Penal Code gives four categories of mens rea:

  1. Purposely

    An act is purposeful if it is the actor's conscious object to engage in the conduct or to cause such a result.

  2. Knowingly

    An act is done knowingly if the actor is aware that his conduct is practically certain to cause such a result.

  3. Recklessly

    An act is reckless if the actor is aware of and consciously disregards a substantial and unjustifiable risk of his conduct causing such a result.

    Unjustifiable Risk

    An unjustified risk must be both substantial and a gross deviation from reasonable standards.

    A gross deviation from reasonable standards means an extreme selfishness.

  4. Negligently

    An act is negligent if the actor should have been aware of the risk of his conduct causing such a result.

Specific Intent

Specific intent means that the act was committed with the intent or desire to bring about the specific result.

Specific intent is required in any offense which requires specific mens rea requirements above and beyond general intent with respect to mens rea.

Strict Liability

Strict liability offenses do not require mens rea.

Analysis if statute does not specify if mens rea required

If a statute does not specify whether mens rea is required or if it is a strict liability offense, the presumption is against strict liability.

To evaluate, always look at, in order: common law, legislative intent, and the penalty.

  • If the offense has a basis in common law, criminal intent is presumed to be required.
    • This presumption can be rebutted by establishing all of:
      1. Clear legislative intent supporting strict liability
      2. Petty penalty
      3. Conviction does not "gravely besmirch"
  • If the offense does not have a basis in common law, the legislative intent must be looked at.
    • If legislative intent is silent on the issue of mental state, the type and penalty of the law must be looked at.
      • If it is a public welfare law and has a petty penalty, it is presumed to be a strict liability offense.
      • If it is not a public welfare law or has non-petty penalties, mens rea is presumed to be required.
    • If legislative intent says mens rea is required, mens rea is required.
    • If legislative intent says that a strict liability offense was intended, the penalty must be examined.
      • If it has a serious penalty (felony), the statute may be unconstitutional.
      • If it has a petty penalty no criminal intent is required.
Causation

For a crime to have been committed, both actual causation and proximate causation are required.

Actual Causation

Actual Causation is determined using the "but for test."

But For Test

The "but for test" establishes actual causation by asking whether the social harm would have occurred when it did but for the defendant's voluntary acts.

Proximate Causation

An actus reus can be the proximate cause of a social harm by being a direct cause or despite an intervening cause.

Direct Cause

A direct cause is one where no event of significance intervened between the actus reus and the social harm.

Intervening Cause

Intervening cause is an independent force that occurs after the defendant's act and is also an actual cause of the harm.

Whether or not an intervening cause breaks proximate causation is usually determined using a foreseeability test.

Factors used in determining if an intervening cause breaks the defendant's proximate causation are:

  • How substantial the defendant's causal responsibility is to that of the intervening cause
    • If insubstantial, unlikely to be foreseeable.
  • Whether the intervening acts were "reasonably foreseeable"
    • The defendant cannot escape liability if the intervening act was "reasonably foreseeable."

An intervening cause can either be responsive to or independent of the defendant's actions.

Responsive Cause

A responsive cause is one that occurs in reaction or response to the defendant's prior wrongful conduct.

A responsive intervening cause generally does not relive the initial wrongdoer of criminal responsibility because it is generally foreseeable.

Independent Cause

An independent cause is a force that does not occur in response to the initial wrongdoer's actions but does occur because of the situation such action placed the victim in.

An independent cause will usually relieve the original wrongdoer of criminal responsibility of the independent cause's harm unless it was foreseeable.

If the other factors do not make it clear, it is unlikely to be proximate cause, but a few miscellaneous factors can still be considered:

  • Whether the intervening cause completes the specific consequences intended by the defendant
  • Whether the defendant's "active force" has come to rest, causing apparent safety, before the intervening cause occurs
  • Whether the intervening cause comprised direct and deliberate human intervention
Homicide

Homicide is the killing of another person.

Criminal homicide is divided into the two broad categories of murder and manslaughter.

Murder
Common Law

At common law, murder is defined as the unlawful killing of another with malice aforethought.

There are four types of common law murder:

  • Intent to kill murder
    • Willful and premeditated
    • Only type to require intentional malice
  • Grievous bodily harm murder
    • If you only intended to cause grievous bodily harm but actually killed him, then that's still murder.
  • Depraved heart murder
  • Felony Murder

    The felony murder rule states one who commits one of the jurisdiction's specified felonies which results in someone's death is guilty of murder.

    Typically, this list includes arson, burglary, rape, and robbery.

    The felony murder rule does have three notable limiting requirements:

    1. Independent Felony

      To trigger the felony murder rule, a felony must be independent from the death caused.

      This is often assessed by asking if the felony would merge into a murder charge because it is a lesser-included charge. If so, it is not independent.

      As an example, an assault that results in a death is not independent. A defendant cannot be convicted of both assault and murder for the same act. In contrast, rape never merges into murder, so the independent felony rule would never apply in such cases.

    2. Inherently Dangerous Felony

      For a felony to trigger the felony murder rule, it must be "inherently dangerous" to human life.

    3. In Furtherance of a Felony

      The killing cannot be too remote from the felony. It must be performed "in furtherance of" the felony.

      Evasion of law enforcement after a crime is usually considered part of the crime's commission.

Model Penal Code

The Model Penal Code defines murder as causing the death of another human being purposely, knowingly, or with extreme recklessness.

Purposely or knowingly is a comparable standard involved in intent to kill murder.

Extreme recklessness basically includes grievous bodily harm murder and depraved heart murder. It is when a person kills another by consciously disregarding a substantial and unjustifiable risk to human life when the risk of death is great.

The Model Penal Code does not exactly follow the felony murder rule but does not eliminate the concept. It creates a rebuttable presumption that killings which occur during the commission of listed dangerous felonies show extreme recklessness.

Manslaughter
Voluntary Manslaughter
Common Law

At common law, voluntary manslaughter is defined as the intentional killing committed in "sudden heat of passion" as the result of "adequate provocation."

  • i.e. Killing another without malice aforethought.

There are four elements to common law manslaughter:

  1. Heat of Passion

    Acting in heat of passion means acting under the effect of a intense emotion such as fear, jealousy, or desperation instead of acting under reason.

    To satisfy the element of manslaughter, the defendant must have acted in heat of passion at the moment of the homicide.

  2. Adequate Provocation

    It is up to the jury to determine what constitutes adequate provocation, but they are typically instructed to apply an objective "reasonable person" standard.

    In most jurisdictions, words are never adequate provocation.

  3. The defendant must not have had a reasonable opportunity to cool off.
  4. There must be a causal link between the provocation, passion, and homicide.
Model Penal Code
MPC § 210.3(1)
  1. Criminal homicide constitutes manslaughter when:
    1. it is committed recklessly; or
    2. a homicide which would otherwise be murder is committed under the influence of extreme mental or emotional disturbance for which there is reasonable explanation or excuse. The reasonableness of such explanation or excuse shall be determined from the viewpoint of a person in the actor's situation under the circumstances as he believes them to be.
Extreme Mental or Emotional Disturbance
MPC § 210.3(1)(b)

[Criminal homicide constitutes manslaughter when] a homicide which would otherwise be murder is committed under the influence of extreme mental or emotional disturbance for which there is reasonable explanation or excuse. The reasonableness of such explanation or excuse shall be determined from the viewpoint of a person in the actor's situation under the circumstances as he believes them to be.

The concept of EMED is intended to incorporate the two common law doctrines of sudden heat of passion (but greatly expanded) and partial responsibility due to diminished capacity.

EMED is broader than the common law provocation defense because:

  1. A specific provocative act is not required.
  2. Even if there is a provocation, it need not involve "an injury, affront, or other provocative act perpetrated upon [the defendant] by the decedent."
  3. Even if the decedent provoked the incident, it need not fall within any fixed category of provocations.
  4. Words alone can warrant a manslaughter instruction.
  5. There is no rigid cooling-off rule. The suddenness requirement of the common law—that the homicide must follow almost immediately after the provocation—is absent form the EMED defense.
Involuntary Manslaughter

Involuntary manslaughter is a common law offense of killing either through recklessness, but without an extreme indifference to human life, or through gross negligence.

It requires either recklessness by consciously disregarding a substantial and unjustifiable risk to human life or gross negligence in failing to be aware of a substantial and unjustifiable risk to human life and committing an act exhibiting a callous disregard for human life.

Grossly Negligent Involuntary Manslaughter

One commits involuntary manslaughter when he kills another through a gross deviation from the standard of care that reasonable people would exercise in the situation.

It is more than tortuous negligence; it must be "so gross" as to be deserving of criminal punishment.

The Model Penal Code does not recognize gross negligence as a basis for involuntary manslaughter, but has a separate offense of negligent homicide.

When one kills another through an act that exhibits extreme indifference to human life, the difference between reckless murder and involuntary manslaughter is that reckless murder requires that the defendant consciously disregard the risk, while involuntary manslaughter only requires that he be grossly negligent by be being unaware of a substantial and unjustifiable risk to human life.

Reckless Involuntary Manslaughter

If one is aware of a substantial and unjustifiable risk to human life and disregards it anyway (recklessness), but his act does not exhibit extreme indifference to human life, he is guilty of involuntary manslaughter.

This is also manslaughter under the Model Penal Code.

Rape

At common law, rape was defined as sexual intercourse by a male with a female not his wife committed without consent and with substantial force overcoming the victim's utmost physical resistance.

Traditionally, statutes have defined rape as sexual intercourse committed forcibly or by threat of force or as sexual intercourse committed without consent and have retained the gender-specific attribute of the common law.

Many states have extended rape law to other forms of non-forcible, but non-consensual, sexual intercourse; to either party being either gender; and to other sexual acts.

The essential elements of rape are generally: sexual intercourse, force or threat of force, and a lack of consent by the victim

Force

Most jurisdictions still require that the perpetrator accomplish the act with either physical force or threat of physical force.

Some jurisdictions interpret their force requirements as merely being the act of sexual penetration itself. In contrast, others require that the force overcome the victim's resistance.

Even states that require that the victim's resistance be overcome differ as to what constitutes resistance. Some require that the victim physically resist and that the defendant physically overpower the victim. Others allow verbal resistance, e.g., saying "no."

Threat of Force

All jurisdictions also allow a threat of force as an alternative to force.

Most jurisdictions require that the threat prevent the victim from resisting due to a reasonable fear or apprehension regarding the victim's physical safety. Non-physical threats do not constitute rape.

Usually this requires both the subjective test of whether the victim had a sincere fear as well as the objective test of whether the fear was objectively reasonable.

Consent

Courts no longer require that the victim "resist to her utmost," only that she not consent.

Some courts view consent as being a communicative act. Thus, consent is given when the victim communicates, verbally or by actions, consent; and consent is revoked when the victim communicates a lack of consent.

Other courts view consent as being a state of mind of the victim. Some of these courts then allow the defendant to argue a mistake of fact defense regarding the victim's lack of consent. Others disallow the defense and thus allow a rape charge even when the defendant believes the victim consented.

Rape by Fraud

Rape can be committed by fraud in the factum, however this is very rare. The more common type of fraud, fraud in the inducement is generally not rape.

Fraud in the Factum

Fraud in the factum means that one deceives another about the nature of the transaction itself. The victim agrees to something, but does not actually understand what they are doing.

An example of fraud in the factum rape is when a victim consents to examination by a doctor, but the doctor engaged in sexual intercourse with the victim instead.

Fraud in the Inducement

Fraud in the inducement means that one deceives another in order to convince the other to do something.

Basically any time someone agrees to have sex with another, they have consented to sex so it cannot be rape. Some jurisdictions have criminalized specific situations however, such as impersonating someone's spouse, such as at night in a dark bedroom.

Sometimes people cannot legally consent to sex, e.g., due to being too young, mentally handicapped, or intoxicated.

Battery

Physical battery is:

  1. An unlawful application of physical force
  2. Resulting in either a physical injury or an offensive touching
  3. Caused purposely, knowingly, or recklessly.
Assault

In most jurisdictions, assault comprises both attempted battery and threats of battery.

Attempt

Attempt liability is the most common form of inchoate liability.

A criminal attempt occurs when a person, with the intent to commit an offense, performs any act that constitutes a substantial step toward the commission of that offense.

A defendant must intend both his conduct and to bring about the crime.

In most jurisdictions, one cannot attempt crimes of recklessness since they do not involve a defendant intending to cause the resulting harm in the first place.

Impossibility

Impossibility is a common defense to attempt crimes. It is divided into factual impossibility and legal impossibility.

Factual Impossibility

Factual impossibility occurs when the defendant's objective is illegal but, unbeknownst to him, impossible to accomplish under the circumstances.

e.g., pointing a gun at someone and pulling the trigger, but the gun jams

Factual impossibility is rarely a valid defense.

Abandonment

Abandonment is a defense to attempt crimes if, after reaching the threshold for the attempt crime, the defendant voluntarily abandons his crime.

Abandonment is not a defense if it occurs as a result of victim resistance or police detection.

For a threat to constitute assault, it must place the victim in a reasonable apprehension of immediate bodily harm. Usually this requires purposely or knowingly causing the apprehension.
Kidnapping

Kidnapping is:

  1. an unlawful confinement or carrying away of the victim
    • "Carrying away" = "asportation"
    • While asportation was traditionally required, most jurisdictions now allow unlawful confinement to satisfy the requirement. Those that keep the asportation requirement punish unlawful confinement as the lesser crime of false imprisonment.
  2. forcibly or by threat, fear, or deception
  3. for a nefarious purpose.
    • What constitutes a nefarious purpose will be given by statute.
Theft

Theft is the unlawful taking of another's property.

Common Law

At common law, theft offenses were segregated into many separate offenses depending on how the property was obtained:

Larceny

Larceny is the trespassory taking and carrying away of another's property with the intent to permanently deprive the possessor of the property.

  • "Trespass" means a legal trespass, i.e., without consent or justification.

Courts later added "larceny by trick" in case the item was taken by ruse.

Theft by False Pretenses

Theft by false pretenses is when one tricks another into giving him actual title to property through fraud.

Embezzlement

Embezzlement is when one has lawful possession of another's property but is then converted with the intent to permanently deprive the owner of the property.

Extortion is also similar to theft:

Extortion

Extortion is the taking of something by threat or fear.

It is very similar to theft.

Model Penal Code

The Model Penal Code and several states have consolidated the various theft crimes into one single theft provision with subcategories.

Regardless of how they are categorized, theft generally requires that the defendant:

  1. Physically take and carry away or
  2. Use deception, fraud, or extortion to take
  3. The victim's property
  4. With the intent to permanently deprive the victim of the property.
Robbery
Common Law

At common law, robbery is the:

  1. Trespassory
  2. Taking and
  3. Carrying away of the
  4. Personal property
  5. Of another
  6. From the presence of the other
  7. Accomplished by means of force or putting in fear
    • Snatching or taking by stealth is usually held to not be sufficient force to constitute robbery unless so attached as to require some force.
    • If resistance is given by the victim, then it constitutes force.
    • A threat must be of injury to a person, not the property.
  8. With intent to steal.
Model Penal Code
MPC § 222.1(1)
  1. Robbery Defined. A person is guilty of robbery if, in the course of committing a theft, he:
    1. inflicts serious bodily injury upon another; or
    2. threatens another with or purposely puts him in fear of immediate serious bodily injury; or
    3. commits or threatens immediately to commit any felony of the first or second degree.
      4. An act shall be deemed “in the course of committing a theft” if it occurs in an attempt to commit theft or in flight after the attempt or commission.
Inchoate Offense

Inchoate offenses are offenses of preparing for and taking steps to commit another crime.

Attempt

Attempt liability is the most common form of inchoate liability.

A criminal attempt occurs when a person, with the intent to commit an offense, performs any act that constitutes a substantial step toward the commission of that offense.

A defendant must intend both his conduct and to bring about the crime.

In most jurisdictions, one cannot attempt crimes of recklessness since they do not involve a defendant intending to cause the resulting harm in the first place.

Impossibility

Impossibility is a common defense to attempt crimes. It is divided into factual impossibility and legal impossibility.

Factual Impossibility

Factual impossibility occurs when the defendant's objective is illegal but, unbeknownst to him, impossible to accomplish under the circumstances.

e.g., pointing a gun at someone and pulling the trigger, but the gun jams

Factual impossibility is rarely a valid defense.

Abandonment

Abandonment is a defense to attempt crimes if, after reaching the threshold for the attempt crime, the defendant voluntarily abandons his crime.

Abandonment is not a defense if it occurs as a result of victim resistance or police detection.

Conspiracy

A conspiracy is an agreement by two or more persons to commit a criminal act.

Conspiracy usually does not merge into a completed offense.

Conspiracy has three elements:

  1. An agreement to commit an unlawful act
    • Can be implied
    • Not all of the parties have to know of every detail of the arrangement, only its essential nature
    • Each person must agree to commit or facilitate some part of the acts leading to the substantive crime.
    • At common law, the object of the agreement does not have to be criminal, but under the Model Penal Code it does.
  2. Specific intent or purpose to achieve the object of the conspiracy
    • Conspiracy requires that the defendant intend to agree and that he intend the result of their agreement to occcur.
      • Some courts and the Model Penal Code require that they purposely bring about the unlawful result, while some others allow a conviction if they merely do it knowingly.
    • The common law adopted the bilateral approach of requiring both the defendant and another to possess the requisite mens rea, however the Model Penal Code and most states have adopted the unilateral approach of only requiring the defendant's culpability.
      • This is especially relevant in situations when the defendant makes a conspiracy with an undercover agent.
  3. Overt act in furtherance of the conspiracy
    • At common law, the conspiracy was complete upon formation of the unlawful agreement. No overt act was required.
    • Most states require proof of the commission of an overt act by any party to the conspiracy. Any act may be sufficient as long as it is in furtherance of the conspiracy. The overt act may be committed before a conspirator joins.
    • The Model Penal Code only requires an overt act in cases involving a misdemeanor or a felony of the third degree.
Abandonment & Renunciation
Common Law

At common law, the conspiracy is committed once an overt act is committed and thus abandonment is not possible.

Model Penal Code

The Model Penal Code allows a conspirator to abandon by renouncing the conspiracy and thwarting the success of the conspiracy. Usually this means contacting the police.

Pinkerton Liability

The Pinkerton liability doctrine says that one is liable for the crimes of his coconspirators as long as such crimes were committed in furtherance of the conspiracy and reasonable forseeable consequences of the conspiracy.

Conspiracy v. Complicity

Although usually an accomplice is a conspirator, conspiracy differs from accomplice liability in several ways:

Solicitation

Solicitation is when one:

  1. Solicits (Asks, hires, encourages, etc.)
  2. A third party to perform a crime and
  3. Has the specific intent or purpose that the third party carry out the crime.

Solicitation usually merges with the solicited offense but usually not with a conspiracy.

The Model Penal Code and many jurisdictions allow a renunciation defense if the defendant prevents the solicitee from carrying out the crime.

Accomplice

Accomplice liability makes one who assists or encourages a criminal to facilitate a crime criminally liable for the crime himself.

The amount of assistance is immaterial; just some amount of assistance is required.

At common law, one could be an accessory after the fact and thereby by convicted of a crime committed by one he helped after the crime was committed. The modern approach however is to make this a separate offense with a much lower penalty.

Merely being present is usually not enough to qualify as encouragement. Rare exceptions exist however. In addition, one may be liable for the crime if he has a preexisting duty to the victim.

While causation is generally required at common law, acts that merely "raise the chance" of harm are sufficient for liability. Many jurisdictions and the Model Penal Code reject the causation requirement altogether and allow liability even when the actor's attempt to aid the principal was ineffective.

Accomplice liability's mens rea requirements are that the defendant must both have the intent to assist the primary party in the conduct that forms the basis of the offense as well as the mental state required for commission of the offense aided.

Some jurisdictions require that the act be performed with the purpose of facilitating the crime, but others only require the knowledge that it would.

Most jurisdictions extend accomplice liability to any other offense that was a natural and probable consequence of the crime aided.

Natural and Probable Consequence

The natural and probable consequences doctrine allows for liability for offenses other than those known to the accomplice.

Under this doctrine, each person is responsible for everything done by his confederates which is the probable and natural consequence of the wrongful act specifically agreed on. The connection between the acts must be reasonably apparent. An unplanned act cannot be a fresh and independent product of the mind of one of the confederates outside of, or foreign to, the common design.

Many jurisdictions and the Model Penal Code reject the doctrine.

Innocent Instrumentality

The innocent instrumentality rule says that one who effects a criminal act through an innocent or unwitting agent (the innocent instrumentality) is a principal in the first degree.

Conspiracy v. Complicity

Although usually an accomplice is a conspirator, conspiracy differs from accomplice liability in several ways:

Defense
Self-Defense

Self-defense is a justification defense when a non-aggressor uses force to defend himself. It requires an honest and reasonable belief that the use of force was necessary to defend against the immediate use of unlawful force and that the force used was reasonably necessary in the circumstances.

The use of force must not be excessive in relation to the harm threatened.

At common law, deadly force is never permitted to repel a non-deadly attack, nor may it be used if a non-deadly response will apparently suffice. The Model Penal Code allows it to protect against immediate death, serious bodily injury, forcible rape, or kidnapping.

The Model Penal Code instead requires that the force be "immediately necessary" to permit force when required to repel the attack instead of when the threat is immediate.

At common law, a person is required to retreat if he can do so in complete safely. However, a slight majority of jurisdictions have enacted stand your ground laws, removing the duty to retreat. In addition, all jurisdictions have an exception to the duty to retreat if one is attacked in his own dwelling place or it curtilage (immediately surrounding land). Some jurisdictions expand this to one's vehicle, and the MPC expands it to one's place of work.

Necessity

Necessity is a justification defense when one commits a relatively minor offense to avoid suffering or allowing another to suffer a substantial harm to person or property.

Elements of necessity:

  1. The defendant must be faced with a clear and imminent danger.
  2. The defendant must have a reasonable expectation that his action will be effective in abating the danger he seeks to avoid.
    • There must be a direct causal relationship between his action and the harm to be averted.
  3. There must be no effective legal way to avert the harm.
  4. The harm that the defendant will cause by violating the law must be less serious than the harm he seeks to avoid.
    • The defendant’s actions should be weighed against the harm reasonably foreseeable at the time, rather than the harm that actually occurs.
  5. Lawmakers must not have previously “anticipated the choice of evils” and determined the balance to be struck in a manner which conflicts with the defendant’s choice.
  6. The defendant must come to the situation with “clean hands”. He must not have substantially contributed to the emergency.

Some states limit the defense to emergencies created by natural, non-human forces.

Necessity cannot apply to homicide cases.

Some courts only allow necessity to protect people and property.

Duress

Duress is an excuse defense when one reasonable believes that committing a crime is:

  1. His only way of rebuffing a
  2. Credible and
  3. Imminent
  4. Threat of death or grievous bodily injury to himself or a member of his family,
  5. While not being at fault for creating the coercive situation.

A crime committed under duress is committed to further the criminal activity of the aggressor, not to resist him.

Intoxication

Intoxication is sometimes a defense.

Neither voluntary nor involuntary were valid defenses at common law.

While voluntary intoxication is still inadmissable as evidence in general intent crimes, many jurisdictions allow it to negate the mens rea element of specific intent crimes.

  • It is not constitutionally required that it ever be allowed as a defense however.

Involuntary intoxication is a complete defense if it causes the defendant to become unable to form the requisite mens rea.

Insanity

Insanity is an excuse defense when one is too insane to warrant criminal punishment.

There are three competing tests for determining insanity:

M'Naghten Test

The M'Naghten test, also known as the cognitive test, says that a person is not guilty by reason of insanity when he, at the time he committed the act:

  1. Had a mental defect
  2. Which either:
    1. Prevented him from knowing the nature and quality of the act he was doing or
    2. From knowing that what he was doing was wrong.
      • Wrongfulness

        Wrongfulness can be understood in one of two ways:

        1. Illegal
        2. Morally wrong
          • Moral wrongfulness can also be determined subjectively or objectively:
            • The objective standard asks whether the actor understood his actions violated society's view of morality.
            • The subjective test asks whether the actor was able to understand that his actions violated his own personal moral code.
Irresistible Impulse Test

Some jurisdictions have established the irresistible impulse test to broaden the M'Naghten test by providing a third prong under which to find a defendant insane—irresistible impulse.

This says that, as an alternative to not knowing the nature and quality of his act or that it was wrong, one may also be found insane if he suffers from a volitional defect that prevents him from complying with the demands of the law.

Model Penal Code Test

The Model Penal Code's "substantial capacity" test includes the irresistible impulse test (and therefore the M'Naghten Test), but further broadens the doctrine by allowing the insanity defence when a criminal retained some capability to under or control his criminal behavior.

This test only requires that a defendant lack the substantial capacity to appreciate the criminal of his conduct or to conform his conduct to the requirements of the law.