Defenses Under Criminal Law
Learning Objective 5: List and briefly define the most important excuse defenses for crimes.
Learning Objective 6: Discuss a common misperception concerning the insanity defense in the United States.
Learning Objective 7: Describe the four most important justification criminal defenses.
A. Criminal Responsibility and the Law
i. Infancy
a. Under the earliest criminal codes of the United States, children under 7 years of age could never be held legally accountable for crimes
b. The accused’s wrongdoing is excused because he or she is too young to fully understand the consequences of his or her actions
| What If Scenario
What if . . . a twelve year old boy, while imitating an action hero he saw on TV using a weapon owned by his dad, kills his best friend. As the twelve year old boy’s lawyer, what defense would you most likely use at his murder trial? At what age do you believe an “infant” is able to understand the consequences of his actions? Should there be an arbitrary age for every type of crime? Why or why not would this be appropriate? |
ii. Insanity
a. When the defendant’s state of mind is such that he or she cannot claim legal responsibility for his or her actions
b. Measuring Sanity
1. A person is excused for his or her criminal wrongdoing if, as a result of mental disease or defect, he or she:
i. does not perceive the physical nature or consequences of his or her actions
ii. does not know that his or her conduct is wrong and/or criminal
iii. is sufficiently unable to control his or her conduct so as to be held accountable for it
2. Diverse tests employed to determine insanity
i. The right-wrong test, or M’Naughten Rule – a person is legally insane and therefore not criminally responsible if, at the time of the offense, he or she was not able to distinguish between right and wrong
ii. The substantial-capacity test, or ALI/MPC test – the defendant lacks “substantial capacity” to either “appreciate the wrongfulness” of his or her conduct or conform that conduct “to the requirements of the law”
iii. Irresistible-impulse test supplemented the M’Naughten Rule – a person may be found insane even if he or she was aware that a criminal act was “wrong” provided that some “irresistible impulse” resulting from a mental deficiency drove him or her to commit the crime
c. Guilty But Mentally Ill
1. Allows a jury to determine that a defendant is “mentally ill” though not insane, and therefore criminally responsible for his or her actions
2. Defendants found guilty but mentally ill spend the early years of their sentence in a psychiatric hospital
d. Determining Competency
1. Psychiatry is commonly used to determine the competency of a defendant to stand trial
2. Competency hearings reveal if the defendant is competent to understand the charges filed against him or her and cooperate with a lawyer presenting a defense
| Media Tool
“A Crime of Insanity” http://www.pbs.org/wgbh/pages/frontline/shows/crime/ · A website maintained by the Public Broadcasting System which delivers information about the insanity defense. |
iii. Intoxication
a. Involuntary
1. Occurs when a person is physically forced to ingest or is injected with an intoxicating substance, or is unaware that a substance contains drugs or alcohol
2. A viable defense to a crime if the substance leaves the person unable to form the mental state necessary to understand that the act committed while under the influence was wrong
b. Voluntary
1. Not a defense in itself
2. Used when arguing that mens rea was negated and was not in the right state of mind that a crime requires
iv. Mistake
a. Mistake of Law
1. Ignorance of the law can be a modified defense
2. If the law was not published or reasonably known to the public
3. If the person relied on an official statement of the law that was erroneous
b. Mistake of Fact
1. Operates as a defense if it negates the mental state necessary to commit a crime
B. Justification Criminal Defenses and the Law
i. Duress
a. Exists when the wrongful threat of one person induces another person to perform an act that she or he would otherwise not perform
b. Requirements must be met:
1. Threat must be of serious bodily harm
2. Harm threatened must be greater than the harm caused by the crime
3. Threat must be immediate and inescapable
4. Defendant must have become involved in the situation through no fault of his or her own
ii. Justifiable Use of Force – Self-Defense
a. A person who believes he or she is in danger of being harmed by another is justified in defending himself or herself with the use of force
b. Defense of one’s dwelling, the defense of other property, and the prevention of a crime are also justified
c. The Amount of Force
1. Generally people can use the amount of nondeadly force necessary to protect themselves, their dwellings, or other property to prevent the commission of a crime
2. Deadly force can be used in self-defense if there is a reasonable belief that imminent death or bodily harm will otherwise result
d. The Duty to Retreat
1. When outside the home or in a public space, some states assert there is a duty to retreat; in other words, deadly force cannot be used if there is an opportunity to “run away” and avoid the conflict
e. The George Zimmerman case
1. Stand your ground law
2. Zimmerman shot and killed unarmed seventeen-year-old Travyon Martin
3. Zimmerman claimed that he had pulled the trigger only after being attacked by Martin
4. Zimmerman was later arrested and put on trial
5. He was not convicted by the jury because he had shown injuries sustained during the encounter with Martin that made his self-defense claims believable to the jury
| Media Tool
Texas Man Found Guilty of Murder in “Stand Your Ground” Shooting; CNN Video http://news.linktv.org/videos/texas-man-guilty-of-murder-in-stand-your-ground-shooting · A short clip about the stand your ground law and its issues |
iii. Necessity
a. Justifiable if “the harm or evil sought to be avoided by such conduct is greater than that sought to be prevented by the law defining the offense charged”
b. Used as a defense against criminal liability in which the defendant asserts that circumstances required him or her to commit an illegal act
iv. Entrapment
a. A justification defense that criminal law allows when a police officer or government agent deceives a defendant into wrongdoing
b. Police cannot persuade a suspect in a criminal act, nor can they coerce a suspect into doing so, even if they are certain he or she is a criminal
Learning Objective 5: List and briefly define the most important excuse defenses for crimes.
Learning Objective 6: Discuss a common misperception concerning the insanity defense in the United States.
Learning Objective 7: Describe the four most important justification criminal defenses.
A. Criminal Responsibility and the Law
i. Infancy
a. Under the earliest criminal codes of the United States, children under 7 years of age could never be held legally accountable for crimes
b. The accused’s wrongdoing is excused because he or she is too young to fully understand the consequences of his or her actions
| What If Scenario
What if . . . a twelve year old boy, while imitating an action hero he saw on TV using a weapon owned by his dad, kills his best friend. As the twelve year old boy’s lawyer, what defense would you most likely use at his murder trial? At what age do you believe an “infant” is able to understand the consequences of his actions? Should there be an arbitrary age for every type of crime? Why or why not would this be appropriate? |
ii. Insanity
a. When the defendant’s state of mind is such that he or she cannot claim legal responsibility for his or her actions
b. Measuring Sanity
1. A person is excused for his or her criminal wrongdoing if, as a result of mental disease or defect, he or she:
i. does not perceive the physical nature or consequences of his or her actions
ii. does not know that his or her conduct is wrong and/or criminal
iii. is sufficiently unable to control his or her conduct so as to be held accountable for it
2. Diverse tests employed to determine insanity
i. The right-wrong test, or M’Naughten Rule – a person is legally insane and therefore not criminally responsible if, at the time of the offense, he or she was not able to distinguish between right and wrong
ii. The substantial-capacity test, or ALI/MPC test – the defendant lacks “substantial capacity” to either “appreciate the wrongfulness” of his or her conduct or conform that conduct “to the requirements of the law”
iii. Irresistible-impulse test supplemented the M’Naughten Rule – a person may be found insane even if he or she was aware that a criminal act was “wrong” provided that some “irresistible impulse” resulting from a mental deficiency drove him or her to commit the crime
c. Guilty But Mentally Ill
1. Allows a jury to determine that a defendant is “mentally ill” though not insane, and therefore criminally responsible for his or her actions
2. Defendants found guilty but mentally ill spend the early years of their sentence in a psychiatric hospital
d. Determining Competency
1. Psychiatry is commonly used to determine the competency of a defendant to stand trial
2. Competency hearings reveal if the defendant is competent to understand the charges filed against him or her and cooperate with a lawyer presenting a defense
| Media Tool
“A Crime of Insanity” http://www.pbs.org/wgbh/pages/frontline/shows/crime/ · A website maintained by the Public Broadcasting System which delivers information about the insanity defense. |
iii. Intoxication
a. Involuntary
1. Occurs when a person is physically forced to ingest or is injected with an intoxicating substance, or is unaware that a substance contains drugs or alcohol
2. A viable defense to a crime if the substance leaves the person unable to form the mental state necessary to understand that the act committed while under the influence was wrong
b. Voluntary
1. Not a defense in itself
2. Used when arguing that mens rea was negated and was not in the right state of mind that a crime requires
iv. Mistake
a. Mistake of Law
1. Ignorance of the law can be a modified defense
2. If the law was not published or reasonably known to the public
3. If the person relied on an official statement of the law that was erroneous
b. Mistake of Fact
1. Operates as a defense if it negates the mental state necessary to commit a crime
B. Justification Criminal Defenses and the Law
i. Duress
a. Exists when the wrongful threat of one person induces another person to perform an act that she or he would otherwise not perform
b. Requirements must be met:
1. Threat must be of serious bodily harm
2. Harm threatened must be greater than the harm caused by the crime
3. Threat must be immediate and inescapable
4. Defendant must have become involved in the situation through no fault of his or her own
ii. Justifiable Use of Force – Self-Defense
a. A person who believes he or she is in danger of being harmed by another is justified in defending himself or herself with the use of force
b. Defense of one’s dwelling, the defense of other property, and the prevention of a crime are also justified
c. The Amount of Force
1. Generally people can use the amount of nondeadly force necessary to protect themselves, their dwellings, or other property to prevent the commission of a crime
2. Deadly force can be used in self-defense if there is a reasonable belief that imminent death or bodily harm will otherwise result
d. The Duty to Retreat
1. When outside the home or in a public space, some states assert there is a duty to retreat; in other words, deadly force cannot be used if there is an opportunity to “run away” and avoid the conflict
e. The George Zimmerman case
1. Stand your ground law
2. Zimmerman shot and killed unarmed seventeen-year-old Travyon Martin
3. Zimmerman claimed that he had pulled the trigger only after being attacked by Martin
4. Zimmerman was later arrested and put on trial
5. He was not convicted by the jury because he had shown injuries sustained during the encounter with Martin that made his self-defense claims believable to the jury
| Media Tool
Texas Man Found Guilty of Murder in “Stand Your Ground” Shooting; CNN Video http://news.linktv.org/videos/texas-man-guilty-of-murder-in-stand-your-ground-shooting · A short clip about the stand your ground law and its issues |
iii. Necessity
a. Justifiable if “the harm or evil sought to be avoided by such conduct is greater than that sought to be prevented by the law defining the offense charged”
b. Used as a defense against criminal liability in which the defendant asserts that circumstances required him or her to commit an illegal act
iv. Entrapment
a. A justification defense that criminal law allows when a police officer or government agent deceives a defendant into wrongdoing
b. Police cannot persuade a suspect in a criminal act, nor can they coerce a suspect into doing so, even if they are certain he or she is a criminal