The following discussion comes from your week 3 readings. Outside research to address these issues is encouraged. I would suggest using the online library for additional sources of information and research. In addition, I would recommend utilizing the legal studies program guide.
Affirmative defenses fall under the categories of justification and excuse. Choose one justification defense (self-defense, duress, etc.) and one excuse defense (infancy, mistake of fact, intoxication, etc.).
Explain how these defenses can be used at trial. Should these types of defenses relieve a person of his or her criminal responsibility?
The defense of duress cannot be used in cases of murder.
Is this exception reasonable, or are there murder cases where this defense should be allowed?
Source: Image courtesy of Jane F. Kardashian, MD.
Working together with a
common criminal purpose
C H A P T E R 7
Parties to Crime
Congress can impute to a corporation the commission of certain criminal offenses and
subject it to criminal prosecution therefor.
– New York Central R. Co. v. U.S., cited in Section 2
1. PARTIES TO CRIME
L E A R N I N G O B J E C T I V E S
1. Identify the four parties to crime at early common law.
2. Identify the parties to crime in modern times.
3. Define the criminal act element required for accomplice liability.
4. Define the criminal intent element required for accomplice liability.
5. Define the natural and probable consequences doctrine.
6. Discuss the consequences of accomplice liability.
7. Determine whether an accomplice can be prosecuted when the principal is not prosecuted or
Often more than one criminal defendant plays a role in the commission of a crime. Defendants work-
ing together with a common criminal purpose or design are acting with complicity. When the parti-
cipation and criminal conduct varies among the defendants, an issue arises as to who is responsible for
which crime and to what degree. This chapter analyzes different parties to crime, along with their ac-
companying criminal liability. Chapter 8 examines crimes that necessarily involve more than one per-
son such as conspiracy and solicitation, as well as another inchoate or incomplete crime, attempt.
principal in the first degree
At early common law, a
defendant who committed a
crime with the help of other
principal in the second
At early common law, a
defendant who was present
at the crime scene and
helped a principal in the first
degree commit a crime.
accessory before the fact
At early common law, a
defendant who was not
present at the crime scene
and helped a principal in the
first degree prepare to
commit a crime.
accessory after the fact
At early common law, a
defendant who helped a
principal escape or avoid
arrest, prosecution for, or
conviction of a crime.
A defendant who commits a
crime with the complicity of
A defendant who helps a
principal commit a crime.
1.1 Accomplice Liability
At early common law, parties to crime were divided into four categories. A principal in the first de-
gree actually committed the crime. A principal in the second degree was present at the scene of the
crime and assisted in its commission. An accessory before the fact was not present at the scene of
the crime, but helped prepare for its commission. An accessory after the fact helped a party to the
crime after its commission by providing comfort, aid, and assistance in escaping or avoiding arrest and
prosecution or conviction.
In modern times, most states and the federal government divide parties to crime into two categor-
ies: principals and their accomplices, and accessories. The criminal actor is referred to as the
principal, although all accomplices have equal criminal responsibility as is discussed in Section 1.
1.2 Accomplice Elements
An accomplice under most state and federal statutes is responsible for the same crime as the criminal
actor or principal. However, accomplice liability is derivative; the accomplice does not actually have
to commit the crime to be responsible for it. The policy supporting accomplice liability is the idea that
an individual who willingly participates in furthering criminal conduct should be accountable for it to
the same extent as the criminal actor. The degree of participation is often difficult to quantify, so stat-
utes and cases attempt to segregate blameworthy accomplices based on the criminal act and intent ele-
ments, as is discussed in Section 1.
In the majority of states and federally, an accomplice must voluntarily act in some manner to assist in
the commission of the offense. Some common descriptors of the criminal act element required for ac-
complice liability are aid, abet, assist, counsel, command, induce, or procure. Examples of actions
that qualify as the accomplice criminal act are helping plan the crime, driving a getaway vehicle after
the crime’s commission, and luring a victim to the scene of the crime. The Model Penal Code defines
the accomplice criminal act element as “aids…or attempts to aid such other person in planning or
committing [the offense]” (Model Penal Code § 2.06(3) (a) (ii)).
In many states, words are enough to constitute the criminal act element required for accomplice li-
ability. On the other hand, mere presence at the scene of the crime, even presence at the scene com-
bined with flight, is not sufficient to convert a bystander into an accomplice. However, if there is a
legal duty to act, a defendant who is present at the scene of a crime without preventing its occurrence
could be liable as an accomplice in many jurisdictions. As the Model Penal Code provides, “[a] per-
son is an accomplice of another person in the commission of an offense if…having a legal duty to pre-
vent the commission of the offense, fails to make proper effect so to do” (Model Penal Code
Example of a Case Lacking Accomplice Act
Review the criminal law issues example in Chapter 1, Section 2. In that example, Clara and Linda go on
a shopping spree. Linda insists that they browse an expensive department store. After they enter the
lingerie department, Linda surreptitiously places a bra into her purse. Clara watches, horrified, but
does not say anything, even though a security guard is standing nearby. As Linda and Clara leave the
store, an alarm is activated. Linda and Clara run away with the security guard in pursuit. In this case,
Clara has probably not committed the criminal act element required for accomplice liability. Although
Clara was present at the scene of the crime and did not alert the security guard, mere presence at the
scene is not sufficient to constitute the accomplice criminal act. Clara fled the scene when the alarm
went off, but presence at the scene of a crime combined with flight is still not enough to comprise the
accomplice criminal act. Thus Clara has probably not committed theft as an accomplice, and only
Linda is subject to a criminal prosecution for this offense.
Example of Accomplice Act
Phoebe, the parent of a two-year-old named Eliza, watches silently as her live-in boyfriend Ricky beats
Eliza. In Phoebe’s state, parents have a duty to come to the aid of their children if their safety is
threatened. Ricky severely injures Eliza, and both Phoebe and Ricky are arrested and charged with bat-
tery and child endangerment. Phoebe probably has committed the criminal act element required for
accomplice liability in many jurisdictions. Phoebe does not personally act to physically harm her child.
However, her presence at the scene combined with a legal duty to act could be enough to make her an
accomplice. Thus Phoebe has most likely committed battery and child endangerment as an accomplice,
and both she and Ricky are subject to a criminal prosecution for these offenses.
174 CRIMINAL LAW
natural and probable
A doctrine that some
jurisdictions follow holding
an accomplice criminally
responsible for all crimes the
principal commits that are
foreseeable when the
accomplice assists the
The criminal intent element required for accomplice liability varies, depending on the jurisdiction. In
many jurisdictions, the accomplice must act with specific intent or purposely when aiding or assisting
the principal. Specific intent or purposely means the accomplice desires the principal to commit the
crime. The Model Penal Code follows this approach and requires the accomplice to act “with the pur-
pose of promoting or facilitating the commission of the offense” (Model Penal Code § 2.06(3) (a)). In
other jurisdictions, if the crime is serious and the accomplice acts with general intent or knowingly or
has awareness that the principal will commit the crime with his or her assistance, intent to further the
crime’s commission could be inferred. In a minority of jurisdictions, only general intent or acting
knowingly that the crime will be promoted or facilitated is required, regardless of the crime’s serious-
Example of Accomplice Intent
Joullian, a hotel owner, rents a hotel room to Winnifred, a prostitute. In a state that requires an accom-
plice to act with specific intent or purposely, Joullian must desire Winnifred to commit prostitution in
the rented room to be Winnifred’s accomplice. Evidence that Joullian stands to benefit from Winni-
fred’s prostitution, such as evidence that he will receive a portion of the prostitution proceeds, could
help prove this intent. If Joullian’s state allows for an inference of specific intent or purposely with seri-
ous crimes when an accomplice acts with general intent or knowingly, it is unlikely that prostitution is
a felony that would give rise to the inference. If Joullian’s state requires only general intent or know-
ingly for accomplice liability regardless of the crime’s seriousness, to be deemed an accomplice Joullian
must simply be aware that renting Winnifred the room will promote or facilitate the act of
The Natural and Probable Consequences Doctrine
Accomplice liability should be imputed only to blameworthy, deserving defendants. However, in some
jurisdictions, if the crime the defendant intentionally furthers is related to the crime the principal actu-
ally commits, the defendant is deemed an accomplice. As with legal causation, discussed in Chapter 4,
foreseeability is the standard. Under the natural and probable consequences doctrine, if the de-
fendant assists the principal with the intent to further a specific crime’s commission, and the principal
commits a different crime that is foreseeable at the time of the defendant’s assistance, the defendant
could be liable as an accomplice. Several jurisdictions have rejected this doctrine as an overly harsh
extension of accomplice liability.
Example of the Natural and Probable Consequences Doctrine
José shows up drunk and unruly at his friend Abel’s house and tells Abel he wants to “beat the hell” out
of his girlfriend Maria. José asks Abel to drive him to Maria’s house, and Abel promptly agrees. Abel
drives José to Maria’s house and waits in the car with the engine running. José forces his way into
Maria’s house and then beats and thereafter rapes her. If José and Abel are in a jurisdiction that recog-
nizes the natural and probable consequences doctrine, the trier of fact could find that Abel is an accom-
plice to the battery, burglary, and rape of Maria. Abel appears to have the criminal intent required to be
an accomplice to battery because he assisted José in his quest to beat Maria. If burglary and rape were
foreseeable when Abel drove a drunk and angry José to Maria’s house, the natural and probable con-
sequences doctrine would extend Abel’s accomplice liability to these crimes. If Abel is not in a natural
and probable consequences jurisdiction, the trier of fact must separately determine that Abel had the
criminal intent required to be an accomplice to battery, burglary, and rape; Abel’s intent will be ascer-
tained according to the jurisdiction’s accomplice intent requirement—either specific intent or pur-
posely or general intent or knowingly.
CHAPTER 7 PARTIES TO CRIME 175
F I G U R E 7 . 1 Diagram of Accomplice Liability
1.3 Consequences of Accomplice Liability
An accomplice is criminally responsible for the crime(s) the principal commits. Although the senten-
cing may vary based on a defendant-accomplice’s criminal record or other extenuating circumstances
related to sentencing, such as prior strikes, in theory, the accomplice is liable to the same degree as the
principal. So if accomplice liability is established in the examples given in Section 1; Phoebe is crimin-
ally responsible for battery and child endangerment, Joullian is criminally responsible for prostitution,
and Abel is criminally responsible for battery and possibly burglary and rape. The principal should also
be criminally responsible for his or her own actions. However, occasionally a situation arises where the
principal is not prosecuted or acquitted because of a procedural technicality, evidentiary problems, or a
plea bargain, as is discussed in Section 1.
Prosecution of an Accomplice When the Principal Is Not Prosecuted or Is Acquitted
Although accomplice liability is derivative, in many jurisdictions the trier of fact can determine that a
defendant is an accomplice even if the criminal actor or principal is not prosecuted or has been tried
and acquitted for the offense. Thus a defendant can be liable for a crime even though he or she did
not commit it and the defendant who did was spared prosecution or found not guilty. While this situ-
ation appears anomalous, if a defendant helps another commit a crime with the intent to further the
crime’s commission, punishment for the completed crime is appropriate. As the Model Penal Code
states, “[a]n accomplice may be convicted on proof of the commission of the offense and of his compli-
city therein, though the person claimed to have committed the offense has not been prosecuted or con-
victed or has been convicted of a different offense or degree of offense…or has been acquitted” (Model
Penal Code § 2.06(7)).
Example of Prosecution of an Accomplice When the Principal Is Not Prosecuted
Review the example in Section 1 with José and Abel. Assume that after José burglarizes, beats, and
rapes Maria, local police arrest José and Abel. The police transport José and Abel to the police station
and take them to separate rooms for interrogation. The police officer who interrogates José is a rookie
and forgets to read José his Miranda rights. Thereafter, the police contact Maria, but she refuses to co-
operate with the investigation because she fears reprisal from José. The district attorney decides not to
prosecute José because of the tainted interrogation. In this case, Abel could still be prosecuted for bat-
tery and possibly rape and burglary as an accomplice in some jurisdictions. Although José is the prin-
cipal and actually committed the crimes, it is not necessary for José to suffer the same criminal prosec-
ution and punishment as Abel. If the elements required for accomplice liability are present, Abel can be
fully responsible for the crimes committed by José, whether or not José is prosecuted for or convicted of
176 CRIMINAL LAW
Garrido Sentencing Video
Attorney: Nancy Garrido in Tears during Sentencing
Phillip Garrido, with his wife Nancy’s help, kidnapped Jaycee Dugard, an eleven-year-old girl, and held her cap-
tive for eighteen years. During that time, Dugard was repeatedly raped, became pregnant twice, and gave
birth to two children. Phillip Garrido pleaded guilty to multiple charges of rape and kidnapping and received a
sentence of four hundred years to life in prison. Nancy was prosecuted as an accomplice, pleaded guilty and
received a sentence of thirty-six years to life in prison. Nancy Garrido’s attorney discusses her sentencing as
an accomplice in this video:
Ghailani Verdict Video
Ghailani Guilty of One Count
Ahmed Ghailani, an alleged terrorist, was transferred from a military prison in Guantanamo Bay and tried as a
civilian in a federal district court in New York. Ghailani was indicted for accomplice liability and conspiracy for
the deaths of hundreds of citizens killed during Al Qaeda bombings of US embassies in Nairobi, Kenya, and
Tanzania. At trial, the prosecution failed to convince the jury that Ghailani had the criminal intent required for
accomplice liability. He was acquitted of the murders and attempted murders as an accomplice and convicted
of one conspiracy charge. However, he received a sentence of life in prison without the possibility of parole for
the conspiracy charge, the same sentence he would have received if convicted of all the murder and attemp-
ted murder charges. A news story on the conviction of Ghailani is shown in this video:
View the video online at: http://www.youtube.com/v/YfCFAmILBQo
View the video online at: http://www.youtube.com/v/ZUVRzJHA_tk
CHAPTER 7 PARTIES TO CRIME 177
K E Y T A K E A W A Y S
< The four parties to crime at early common law were principals in the first degree, principals in the second
degree, accessories before the fact, and accessories after the fact. These designations signified the
< Principals in the first degree committed the crime.
< Principals in the second degree were present at the crime scene and assisted in the crime’s
< Accessories before the fact were not present at the crime scene, but assisted in preparing for the
< Accessories after the fact helped a party to the crime avoid detection and escape prosecution or
< In modern times, the parties to crime are principals and their accomplices, and accessories.
< The criminal act element required for accomplice liability is aiding, abetting, or assisting in the commission
of a crime. In many jurisdictions, words are enough to constitute the accomplice criminal act element,
while mere presence at the scene without a legal duty to act is not enough.
< The criminal intent element required for accomplice liability is either specific intent or purposely or general
intent or knowingly.
< The natural and probable consequences doctrine holds an accomplice criminally responsible if the crime
the principal commits is foreseeable when the accomplice assists the principal.
< The consequences of accomplice liability are that the accomplice is criminally responsible for the crimes
the principal commits.
< In many jurisdictions, an accomplice can be prosecuted for an offense even if the principal is not
prosecuted or is tried and acquitted.
E X E R C I S E S
Answer the following questions. Check your answers using the answer key at the end of the chapter.
1. Justin asks his girlfriend Penelope, a bank teller, to let him know what time the security guard takes his
lunch break so that he can successfully rob the bank. Penelope tells Justin the security guard takes his
break at 1:00. The next day, which is Penelope’s day off, Justin successfully robs the bank at 1:15. Has
Penelope committed robbery? Why or why not?
2. Read State v. Ulvinen, 313 N.W.2d 425 (1981). In Ulvinen, the defendant sat guard and then helped her son
clean up and dispose of evidence after he strangled and dismembered his wife. Thereafter, the defendant
was convicted of murder as an accomplice. The defendant was asleep when the killing occurred, but
before the killing her son told her that he planned to kill the victim. The defendant reacted with passive
acquiescence by demurring and expressing disbelief that he would go through with his plans. Did the
Supreme Court of Minnesota uphold the defendant’s murder conviction? The case is available at this link:
3. Read Joubert v. State, 235 SW 3d 729 (2007). In Joubert, the defendant was convicted and sentenced to
death based on his participation in an armed robbery that resulted in the death of a police officer and
employee. The jury convicted the defendant after hearing testimony from his accomplice and reviewing a
video of the defendant confessing to the offense. The defendant appealed the conviction because in
Texas, accomplice testimony must be corroborated by other evidence, and the defendant claimed that
the other corroborating evidence was lacking in this case. Did the Court of Criminal Appeals of Texas
uphold the defendant’s conviction? Why or why not? The case is available at this link:
178 CRIMINAL LAW
The transfer of a defendant’s
liability based upon a special
The vicarious liability of a
2. VICARIOUS LIABILITY
L E A R N I N G O B J E C T I V E S
1. Distinguish between accomplice liability and vicarious liability.
2. Distinguish between corporate criminal vicarious liability and individual criminal vicarious
Vicarious liability, a concept discussed in Chapter 4, also transfers liability from one defendant to
another. However, vicarious liability should not be confused with accomplice liability. Accomplice liab-
ility is based on the defendant’s participation in a criminal enterprise and complicity with the criminal
actor or principal, but vicarious liability transfers a defendant’s criminal responsibility for the crime to
a different defendant because of a special relationship. With vicarious liability, the acting defendant also
is criminally responsible for his or her conduct. Similar to the civil law concept of respondeat superior
discussed in Chapter 1, vicarious liability in criminal law is common between employers and employ-
ees. It is also the basis of corporate liability, which is discussed in Section 2.
2.1 Corporate Liability
At early common law, corporations were not criminally prosecutable as separate entities, which was
most likely because in England, corporations were owned and operated by the government. In modern
times, American corporations are private enterprises whose actions can seriously injure other individu-
als and the economy. Thus a corporation can be criminally responsible for conduct apart from its own-
ers, agents, or employees. In general, this is a vicarious liability, transferring criminal responsibility
for an offense from an agent or employee of the corporation to the corporation itself, based on the em-
ployment relationship. Of course, the agent or employee also is responsible for the crime he or she
A corporation is vicariously liable only if an agent or employee commits a crime during the agent
or employee’s scope of employment. As the Model Penal Code states, “[a] corporation may be con-
victed of the commission of an offense if…the conduct is performed by an agent of the corporation act-
ing in behalf of the corporation within the scope of his office or employment” (Model Penal Code
§ 2.07(1)(a)). The criminal punishment for a corporation is generally payment of a fine.
Example of Corporate Liability
Harry, an employee of Burger King Corporation, shreds corporate documents in his office when Bur-
ger King is sued civilly for sexual harassment in a multimillion-dollar class action suit. Under modern
theories of corporate liability, both Harry and Burger King could be criminally prosecuted for obstruc-
tion of justice. Note that Burger King’s liability is vicarious and depends on its relationship with Harry
as an employer and the fact that Harry is acting within the scope of employment. Vicarious liability is
distinguishable from accomplice liability, where the accomplice must be complicit with the criminal
actor. The owners of Burger King, who are the corporate shareholders, did not actively participate in
Harry’s conduct, although they will share in the punishment if the corporation is fined.
CHAPTER 7 PARTIES TO CRIME 179
F I G U R E 7 . 2 Vicarious and Corporate Liability
2.2 Individual Criminal Vicarious Liability
Generally speaking, criminal law disfavors criminal vicarious liability, the exception being corporate
liability discussed in Section 2. Criminal vicarious liability violates the basic precept that individuals
should be criminally accountable for their own conduct, not the conduct of others. Although ac-
complice liability appears to hold an accomplice responsible for principals’ conduct, in reality the ac-
complice is committing a criminal act supported by criminal intent and is punished accordingly. In ad-
dition, other statutes that appear to impose criminal liability vicariously are actually holding individu-
als responsible for their own criminal conduct. Some examples are statutes holding parents criminally
responsible when their children commit crimes that involve weapons belonging to the parents, and
offenses criminalizing contributing to the delinquency of a minor. In both of these examples, the par-
ents are held accountable for their conduct, such as allowing children to access their guns or be truant
from school. The law is evolving in this area because the incidence of juveniles committing crimes is
becoming increasingly prevalent.
K E Y T A K E A W A Y S
< Accomplice liability holds an accomplice accountable when he or she is complicit with the principal;
vicarious liability imposes criminal responsibility on a defendant because of a special relationship with the
< In many jurisdictions, corporations are vicariously liable for crimes committed by employees or agents
acting within the scope of employment. Individual criminal vicarious liability is frowned on, but the law in
this area is evolving as the incidence of juveniles committing crimes increases.
180 CRIMINAL LAW
E X E R C I S E S
Answer the following questions. Check your answers using the answer key at the end of the chapter.
1. Brad, the president and CEO of ABC Corporation, recklessly hits and kills a pedestrian as he is driving home
from work. Could ABC Corporation be held vicariously liable for criminal homicide? Why or why not?
2. Read People v. Premier House, Inc., 662 N.Y.S 2d 1006 (1997). In Premier House, the defendant, a housing
cooperative that was incorporated, and members of the housing cooperative board of directors were
ordered to stand trial for violating a New York law requiring that window guards be installed on apartment
buildings. A child died after falling out of one of the windows. The members of the board of directors
appealed on the basis that their positions were merely honorary, and they had no personal involvement in
the crime. Did the Criminal Court of the City of New York uphold the order as to the members of the board
of directors? Why or why not? The case is available at this link: http://scholar.google.com/
3. Read Connecticut General Statute § 53a-8(b), which criminalizes the sale or provision of a firearm to
another for the purpose of committing a crime. The statute is available at this link: http://law.justia.com/
connecticut/codes/2005/title53a/sec53a-8.html. Does this statute create accomplice liability or
vicarious liability? Read the Connecticut Criminal Jury Instruction 3.1-4 for an explanation of the statute.
The jury instruction is available at this link: http://www.jud.ct.gov/ji/criminal/part3/3.1-4.htm.
L A W A N D E T H I C S : L I F E C A R E C E N T E R S O F A M E R I C A ,
I N C .
Is a Corporation Criminally Accountable When Its Employees Are Not?
Read Commonwealth v. Life Care Centers of America, Inc., 456 Mass. 826 (2010). The case is available at this link:
scholar_case?case=12168070317136071651&hl=en&as_sdt=2&as_vis=1&oi=scholarr. In Life Care Centers, a res-
ident of the Life Care Center nursing home died in 2004 from injuries sustained when she fell down the front
stairs while attempting to leave the facility in her wheelchair. The resident could try to leave the facility be-
cause she was not wearing a prescribed security bracelet that both set off an alarm and temporarily locked
the front doors if a resident approached within a certain distance of those doors. The defendant, Life Care
Centers of America, Inc., a corporation that operates the nursing home, was indicted for involuntary man-
slaughter and criminal neglect. The criminal intent element required for involuntary manslaughter and
criminal neglect in Massachusetts is reckless intent. The evidence indicated that the order requiring the vic-
tim to wear a security bracelet was negligently edited out of the victim’s treatment sheet, based on the actions
of more than one employee. The individual employee who left the victim near the stairs without the security
bracelet relied on the orders that did not indicate a need for the bracelet. There was no evidence that any indi-
vidual employee of Life Care Centers of America, Inc. was reckless. The prosecution introduced a theory of
“collective knowledge” of the actions or failure to act of the corporation’s employees. The prosecution’s
premise was that the several individual instances of negligent conduct combined to create reckless conduct
that could be imputed to the corporation vicariously. The Massachusetts Supreme Court unanimously held
that the corporation could not be held criminally responsible unless one individual employee could be held
1. Do you think it is ethical to allow a corporation to escape criminal responsibility for reckless involuntary
manslaughter and criminal neglect when several employees’ negligent conduct caused the death, rather
than one employee’s reckless conduct? Why or why not?
Check your answer using the answer key at the end of the chapter.
CHAPTER 7 PARTIES TO …
Source: Image courtesy of Tara Storm.
A defense that excuses a
legally insane defendant’s
C H A P T E R 6
Criminal Defenses, Part 2
The use of drugs or controlled substances, dependence on drugs or controlled substances or
voluntary intoxication shall not, as such, constitute a defense to a criminal charge…
– Or. Rev. Stat. § 161.125(1), cited in Section 2
1. THE INSANITY DEFENSE
L E A R N I N G O B J E C T I V E S
1. Identify four states that do not recognize an insanity defense.
2. Identify four versions of the insanity defense.
3. Ascertain the two elements required for the M’Naghten insanity defense.
4. Ascertain the two elements required for the irresistible impulse insanity defense.
5. Compare the M’Naghten, irresistible impulse, and substantial capacity tests.
6. Ascertain the basis of the Durham insanity defense.
7. Identify the various burdens of proof for the insanity defense.
8. Distinguish between diminished capacity and the insanity defense.
9. Compare the insanity defense with mental competence to stand trial.
10. Compare the insanity defense with the guilty but mentally ill verdict.
11. Compare different commitment procedures for an insane criminal defendant.
12. Distinguish temporary from permanent insanity.
With the exception of alibi and the expiration of the statute of limitations, Chapter 5 explored criminal
defenses based on justification. This chapter reviews criminal defenses based on excuse, including the
insanity defense. Remember that defenses based on excuse focus on the defendant and claim that the
defendant should be excused from criminal responsibility for his or her conduct under the
Although controversial, most states and the federal government recognize an insanity defense.
Montana, Utah, Kansas, and Idaho are the only states that do not. The insanity defense is the subject
of much debate because it excuses even the most evil and abhorrent conduct, and in many jurisdic-
tions, legal insanity functions as a perfect defense resulting in acquittal. However, the insanity defense
is rarely used and hardly ever successful. This is generally because of the difficulty in proving legal
Many criminal defendants suffer from mental illness and can produce evidence of this illness such
as psychiatric or layperson testimony. Often, mental disturbance is apparent from the defendant’s con-
duct under the circumstances. However, legal insanity differs from medical insanity and is generally
much more difficult to establish. The rationale behind creating a different standard for legal insanity is
the goal of a criminal prosecution discussed in Chapter 1. Criminal prosecution should deter as well as
incapacitate. While the purpose of a medical diagnosis is to eventually cure the defendant’s disorder,
the purpose of criminal law is to punish the defendant. Thus the defendant’s conduct is not excused if
the defendant or society can benefit from punishment.
The policy supporting the insanity defense is twofold. First, an insane defendant does not have
control over his or her conduct. This is similar to a defendant who is hypnotized, or sleepwalking. Se-
cond, an insane defendant does not have the ability to form criminal intent. Without the ability to con-
trol conduct, or the understanding that conduct is evil or wrong by society’s standards, an insane de-
fendant presumably will commit crimes again and again. Thus no deterrent effect is served by punish-
ment, and treatment for the mental defect is the appropriate remedy.
Four variations of the insanity defense currently exist: M’Naghten, irresistible impulse, substantial
capacity, and Durham.
An insanity defense that
excuses criminal conduct
when a mental defect or
disease caused the defendant
not to know the nature or
quality of the criminal act, or
that the act was wrong. Also
called the right-wrong test.
The defendant claims God
commanded him or her to
commit the crime.
1.1 M’Naghten Insanity Defense
The M’Naghten insanity defense, also called the right-wrong test, is the most common insanity de-
fense in the United States. It is also the oldest and was created in England in 1843. The defense is
named after Daniel M’Naghten. M’Naghten was under the paranoid delusion that the Prime Minister
of England, Sir Robert Peel, was trying to kill him. When he tried to shoot Sir Peel from behind, he in-
advertently shot Sir Peel’s Secretary, Edward Drummond, who thereafter died. M’Naghten was put on
trial for murder and, to the shock of the nation, the jury found him not guilty by reason of insanity.
After a public outcry at this verdict, the British House of Lords developed a test for insanity that re-
mains relatively intact today.
The M’Naghten insanity defense is cognitive and focuses on the defendant’s awareness, rather than
the ability to control conduct. The defense requires two elements. First, the defendant must be suffering
from a mental defect at the time he or she commits the criminal act. The mental defect can be called a
“defect of reason” or a “disease of the mind,” depending on the jurisdiction. Second, the trier of fact
must find that because of the mental defect, the defendant did not know either the nature and quality
of the criminal act or that the act was wrong.
The terms “defect of reason” and “disease of the mind” can be defined in different ways, but in
general, the defendant must be cognitively impaired to the level of not knowing the nature and quality
of the criminal act, or that the act is wrong. Some common examples of mental defects and diseases are
psychosis, schizophrenia, and paranoia.
Jurisdictions vary as to the level of awareness the defendant must possess. Some jurisdictions use
the term “know,” or “understand,” while others use the term “appreciate.” If know or understand is
the standard, the trier of fact must ascertain a basic level of awareness under the attendant circum-
stances. If appreciate is the standard, the trier of fact must analyze the defendant’s emotional state, and
evidence of the defendant’s character or personality may be relevant and admissible.
A defendant does not know the nature and quality of a criminal act if the defendant is completely
oblivious to what he or she is doing. This is quite rare, so most defendants claiming insanity choose to
assert that they did not know their act was wrong. However, jurisdictions differ as to the meaning of
“wrong.” Some jurisdictions define wrong as “legally wrong,” meaning the defendant must be unaware
that the act is against the law. Others define wrong as “legally and morally wrong,” meaning the de-
fendant must also be unaware that the act is condemned by society. Generally, the only instance
where the defendant must be “morally wrong,” standing alone, is when the defendant claims that the
conduct was performed at the command of God, which is called the deific defense. Whether the
standard is legally wrong or morally wrong, if there is any evidence of a cover-up or an attempt to hide
or escape, it is apparent that the defendant knew the difference between right and wrong, defeating the
claim of insanity under M’Naghten.
Example of a Case Inappropriate for the M’Naghten Insanity Defense
Susan wants to marry a single man, but he does not want the responsibility of caring for her children.
Susan decides to kill her children. She drives her two sons, aged three and five, out to the lake. She puts
the car in park, gets out, and then puts it in gear, watching as it drives into the water. Both of her sons
drown. Later that day, Susan files a police report stating that a stranger kidnapped her children at gun-
point. While searching the area for the kidnapper, the police discover the children’s bodies and evid-
ence indicating that Susan killed them.
Susan recants her kidnapping story and admits she killed her children. However, she claims she is
not guilty by reason of insanity. Susan’s claim will probably not be successful if she killed her children
in a jurisdiction that recognizes the M’Naghten insanity defense. Susan tried to mislead the police,
demonstrating her awareness that she had done something wrong. Thus although Susan’s behavior ap-
pears mentally imbalanced, she clearly knew the difference between right and wrong, and her conduct is
not excusable under M’Naghten’s rigid requirements.
Example of a Case Appropriate for the M’Naghten Insanity Defense
Andrea, a diagnosed schizophrenic, drowns five of her young children in the bathtub. Andrea
promptly phones 911 and tells the operator that her children are dead. The operator dispatches an
emergency call to law enforcement. When law enforcement officers arrive at Andrea’s house, she in-
forms them that she killed her children so that they could leave this earth and enter heaven.
Andrea thereafter claims she is not guilty for killing her children by reason of insanity. Andrea
could be successful if the jurisdiction in which she killed her children recognizes the M’Naghten insan-
ity defense. Andrea suffers from a mental defect, schizophrenia. In addition, there is no evidence indic-
ating Andrea knew her conduct was wrong, such as an attempted escape, or cover-up. In fact, Andrea
herself contacted law enforcement and immediately told them about her criminal acts. Thus both of the
146 CRIMINAL LAW
irresistible impulse defense
An insanity defense that
excuses criminal conduct
when a mental defect or
disease caused the defendant
to lose the ability to control
his or her conduct or
conform his or her conduct
to the law.
M’Naghten elements appear to be present, and Andrea’s conduct may be excusable under the
F I G U R E 6 . 1 M’Naghten Insanity Defense
1.2 Irresistible Impulse Insanity Defense
Another variation of the insanity defense is the irresistible impulse defense. This defense has lost
popularity over the years and is rejected by most of the states and the federal government. In some
cases, the irresistible impulse insanity defense is easier to prove than the M’Naghten insanity defense,
resulting in the acquittal of more mentally disturbed defendants.
The irresistible impulse insanity defense generally supplements M’Naghten, so the focus is on the
defendant’s awareness (cognitive) and the defendant’s will (ability to control conduct). In jurisdictions
that recognize the irresistible impulse insanity defense, the first element is the same as M’Naghten; the
defendant must suffer from a mental defect or disease of the mind. However, the second element adds
the concept of volition, or free choice. If the defendant cannot control his or her conduct because of
the mental defect or disease, the defendant’s conduct is excused even if the defendant understands that
the conduct is wrong. This is a softer stance than M’Naghten, which does not exonerate a defendant
who is aware conduct is wrong. The challenge for the trier of fact in an irresistible impulse jurisdiction
is distinguishing between conduct that can be controlled and conduct that cannot.
Example of a Case Inappropriate for the Irresistible Impulse Insanity Defense
Jolene, who has been diagnosed with paranoia, decides she must cut off all her sorority sisters’ hair be-
cause they are “out to get her.” She drives to the sorority house with a Taser and scissors in her back-
pack. Her plan is to subdue each sister with the stun gun and then hack off her hair. As she arrives at
the house, she sees Agnes, one of her sorority sisters, trip and fall in the parking lot, ripping her
cashmere sweater and scraping her chin. Feeling a stab of pity, Jolene ignores Agnes and walks hur-
riedly toward the building. As she enters, Ashley, another sorority sister, turns, scowls at Jolene, and
barks, “What in the world are you wearing? You look like you just rolled out of bed!” Jolene pulls the
stun gun out of her backpack and shoots Ashley. While Ashley is lying on the floor, Jolene takes out the
scissors and cuts Ashley’s hair off at the scalp.
CHAPTER 6 CRIMINAL DEFENSES, PART 2 147
substantial capacity test
An insanity defense that
excuses criminal conduct
when a mental disease or
defect caused the defendant
to lose the substantial
capacity to appreciate the
criminality of conduct, or to
control conduct or conform
conduct to the law. Also
called the Model Penal Code
or ALI insanity defense.
Jolene claims she is not guilty for assault and battery of Ashley by reason of insanity. If Jolene at-
tacked Ashley in a jurisdiction that recognizes the irresistible impulse insanity defense, she probably
will not be successful with her claim. Jolene has been diagnosed with paranoia, which is a mental defect
or disease. However, Jolene seems aware that shooting someone with a stun gun and cutting off her
hair is wrong because she spared Agnes based on pity. In addition, Jolene’s choice not to attack Agnes
indicates she has control over her conduct. Thus Jolene is cognitive of the difference between right and
wrong and has the will to suppress criminal behavior, defeating any claim of insanity under the irresist-
ible impulse insanity defense.
F I G U R E 6 . 2 Irresistible Impulse Insanity Defense
1.3 The Substantial Capacity Test
The substantial capacity test is the insanity defense created by the Model Penal Code. The Model
Penal Code was completed in 1962. By 1980, approximately half of the states and the federal govern-
ment adopted the substantial capacity test (also called the Model Penal Code or ALI defense).
However, in 1982, John Hinckley successfully claimed insanity using the substantial capacity test in his
federal trial for the attempted murder of then-President Ronald Reagan. Public indignation at this not-
guilty verdict caused many states and the federal government to switch from the substantial capacity
test to the more inflexible M’Naghten standard. In addition, jurisdictions that switched to
M’Naghten also shifted the burden of proving insanity to the defendant. The defendant’s burden of
proof for the insanity defense is discussed shortly.
The substantial capacity test is as follows: “A person is not responsible for criminal conduct if at
the time of such conduct as a result of mental disease or defect he lacks substantial capacity either to
appreciate the criminality [wrongfulness] of his conduct or to conform his conduct to the requirements
of law” (Model Penal Code § 4.01(1)). The defense has two elements. The first element requires the de-
fendant to have a mental disease or defect, like the M’Naghten and irresistible impulse insanity de-
fenses. The second element combines the cognitive standard with volitional, like the irresistible im-
pulse insanity defense supplementing the M’Naghten insanity defense.
In general, it is easier to establish insanity under the substantial capacity test because both the cog-
nitive and volitional requirements are scaled down to more flexible standards. Unlike the M’Naghten
148 CRIMINAL LAW
insanity defense, the substantial capacity test relaxes the requirement for complete inability to under-
stand or know the difference between right and wrong. Instead, the defendant must lack substantial,
not total, capacity. The “wrong” in the substantial capacity test is “criminality,” which is a legal rather
than moral wrong. In addition, unlike the irresistible impulse insanity defense, the defendant must lack
substantial, not total, ability to conform conduct to the requirements of the law. Another difference in
the substantial capacity test is the use of the word “appreciate” rather than “know.” As stated previ-
ously, appreciate incorporates an emotional quality, which means that evidence of the defendant’s
character or personality is relevant and most likely admissible to support the defense.
Example of the Substantial Capacity Test
Loreen has been diagnosed with psychosis and spent most of her life in a mental hospital. While at the
mental hospital, Loreen made friends with many of the patients and health-care personnel. From time
to time, Loreen would play jokes on these friends. Most of these “jokes” consisted of putting her antide-
pressants into their food. Loreen was always reprimanded and often sternly punished for these es-
capades. After her release from the mental hospital at age twenty-one, Loreen falls in love with Aidan, a
man who works in a bookstore near her apartment. Loreen decides to make Aidan fall in love with her
by feeding him a magic potion, which she concocts out of a mixture of her antidepressants. Loreen
buys a book from Aidan and casually asks if he would like her to buy him a coffee. Aidan shrugs and
says, “Sure, but I don’t have a break for another two hours.” Loreen offers to bring him the coffee. Be-
fore bringing the drink to Aidan, she puts her “magic potion” in it. While Aidan is sipping the coffee,
Loreen declares her love for him. She then states, “I know I shouldn’t have, but I put a love potion in
your coffee. I hope it doesn’t hurt you.” Aidan becomes seriously ill after drinking the coffee and is
Loreen claims she is not guilty for battering Aidan by reason of insanity. If Loreen is in a jurisdic-
tion that recognizes the substantial capacity test, she may be successful with her claim. Loreen has a
mental disease or defect, psychosis. Loreen’s statement to Aidan indicates that she lacks the substantial
capacity to appreciate the criminality of her conduct. Note that if Loreen were in a M’Naghten jurisdic-
tion, her statement “I know I shouldn’t have” could prove her awareness that her conduct was wrong,
defeating her claim. In addition, Loreen’s behavior at the mental hospital indicates that she lacks the
substantial capacity to conform or control her conduct. Even after a lifetime of being punished over
and over for mixing her meds together and putting them in other people’s food or drink, Loreen still
does it. Lastly, in a substantial capacity jurisdiction, testimony from Loreen’s friends at the mental hos-
pital may be admissible to support her claim of insanity, and her lack of ability to “appreciate” the
criminality of her conduct.
CHAPTER 6 CRIMINAL DEFENSES, PART 2 149
Durham insanity defense
An insanity defense that
excuses criminal conduct
when it is caused by a mental
disease or defect. Also called
the product test.
F I G U R E 6 . 3 Substantial Capacity Insanity Defense
1.4 The Durham Insanity Defense
The Durham insanity defense is used only in New Hampshire and has been the established insanity
defense in New Hampshire since the late 1800s. The Durham defense, also called the Durham rule or
the product test, was adopted by the Circuit Court of Appeals for the District of Columbia in the case
of Durham v. U.S., 214 F.2d 862 (1954). The defense set forth in that case is as follows: “[A]n accused is
not criminally responsible if his unlawful act was the product of mental disease or mental defect.”
However, the court failed to give definitions for product, mental disease, or mental defect. Thus the
Durham insanity defense is extremely difficult to apply, and the D.C. Circuit rejected it in 1972 in the
case of U.S. v. Brawner, 471 F.2d 969 (1972), which was later superseded by federal statute.
In general, the Durham insanity defense relies on ordinary principles of proximate causation. The
defense has two elements. First, the defendant must have a mental disease or defect. Although these
terms are not specifically defined in the Durham case, the language of the judicial opinion indicates an
attempt to rely more on objective, psychological standards, rather than focusing on the defendant’s
subjective cognition. The second element has to do with causation. If the criminal conduct is “caused”
by the mental disease or defect, then the conduct should be excused under the circumstances.
Example of the Durham Insanity Defense
Arianna has been diagnosed with paranoia. Most psychiatric experts agree that individuals afflicted
with paranoia unreasonably believe that the human population is “out to get them.” Arianna works un-
der the direct supervision of Nora, who has a physical condition called “walleye.” Nora’s walleye makes
it appear that she is looking to the side when she addresses people. Arianna gradually becomes con-
vinced that Nora is communicating secret messages to their coworkers when she is speaking to Ari-
anna. Arianna is genuinely frightened that Nora is telling their coworkers to kill her, and she decides
she needs to defend herself. Arianna brings a gun to work one day, and when Nora begins talking to
her about her tendency to take overlong lunches, Arianna pulls the gun out of her cubicle and shoots
and kills Nora.
Arianna claims she is not guilty for killing Nora by reason of insanity. If Arianna killed Nora in
New Hampshire, she might be successful with her claim. Arianna has a mental disease or defect,
150 CRIMINAL LAW
paranoia. Arianna can probably produce evidence, such as psychiatric expert testimony, that her para-
noia “caused” or “produced” her criminal conduct, which was shooting Nora. Thus a trier of fact could
acquit Arianna on the grounds that her conduct is excusable under these circumstances.
F I G U R E 6 . 4 Durham Insanity Defense
1.5 Proving Insanity
There is generally a presumption that criminal defendants are sane, just as there is a presumption that
they are innocent. Therefore, at a minimum, a defendant claiming insanity must produce evidence that
rebuts this presumption. Some states require the prosecution to thereafter prove sanity beyond a reas-
onable doubt or to a preponderance of evidence.
Post-Hinckley, many states have converted the insanity defense into an affirmative defense. Thus
as discussed in Chapter 5, the defendant may also have the burden of persuading the trier of fact that
he or she is insane to a preponderance of evidence. The federal government and some other states
require the defendant to prove insanity by clear and convincing evidence, which is a higher standard
than preponderance of evidence.
CHAPTER 6 CRIMINAL DEFENSES, PART 2 151
An imperfect failure of proof
defense that reduces
first-degree murder to
second-degree murder or
manslaughter if the
defendant did not have the
mental capacity to form
first-degree murder criminal
A failure of proof defense that
claims a syndrome prevented
the defendant from forming
the requisite intent for the
mental competence to
The defendant cannot be put
on trial if the defendant is
incapable of understanding
the proceedings against him
or her or assisting in his or her
defense because of mental
guilty but mentally ill
A verdict that deems the
criminal defendant mentally
ill and orders the criminal
defendant to mental health
treatment while incarcerated.
1.6 Diminished Capacity
A claim of diminished capacity differs from the insanity defense. Diminished capacity is an imper-
fect failure of proof defense recognized in a minority of jurisdictions. Diminished capacity could re-
duce a first-degree murder charge to second-degree murder or manslaughter if the defendant lacks the
mental capacity to form the appropriate criminal intent for first-degree murder.
In California, diminished capacity was abolished as an affirmative defense after San Francisco Su-
pervisor Dan White used it successfully in his trial for the murder of fellow Supervisor Harvey Milk. A
jury convicted White of voluntary manslaughter rather than first-degree premeditated murder after re-
viewing evidence that proved his diet of junk food (Twinkies) created a chemical imbalance in his
brain. In the aftermath of this highly publicized trial, California passed legislation eliminating the di-
minished capacity defense and limiting the admissibility of evidence of diminished capacity only to
Similar to diminished capacity is the syndrome defense. A syndrome that negates the requisite
intent for the crime could function as a failure of proof defense in a minority of jurisdictions. Some
common examples of syndromes the American Psychiatric Association recognizes in the Diagnostic
and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), are antisocial personality dis-
order, posttraumatic stress disorder, and intermittent explosive disorder. Some common examples of
syndromes identified but not recognized in DSM-IV are battered woman or battered wife syndrome
(discussed in Chapter 5) and caffeine withdrawal. Although successful use of the syndrome defense is
rare, at least one case has excused a defendant’s drunken driving and assault and battery against a po-
lice officer because of premenstrual syndrome (PMS).
1.7 Mental Competence to Stand Trial
The insanity defense is different from mental competence to stand trial. The insanity defense per-
tains to the defendant’s mental state when he or she commits the crime. If the insanity defense is suc-
cessful, it exonerates the defendant from guilt. Mental competence to stand trial is analyzed at the time
the trial is to take place. If the defendant is mentally incompetent to stand trial, the trial is delayed until
the defendant regains competency. Although a detailed discussion of mental competence to stand trial
is beyond the scope of this book, in general, a criminal defendant must be able to understand the
charges against him or her, and be able to assist in his or her defense. As the Model Penal Code
provides, “[n]o person who as a result of mental disease or defect lacks capacity to understand the pro-
ceedings against him or to assist in his own defense shall be tried, convicted or sentenced for the com-
mission of an offense so long as such incapacity endures” (Model Penal Code § 4.04). A defendant who
is mentally incompetent at the time of trial is subject to mental health treatment or even involuntary
medication until competence is regained.
1.8 Guilty but Mentally Ill
Post-Hinckley, some states adopted the guilty but mentally ill verdict. A defendant who is found
guilty but mentally ill is not acquitted but punished and treated for mental health simultaneously while
in prison. Typically, the guilty but mentally ill verdict is available only when the defendant fails to
prove legal insanity, and requires the defendant to prove mental illness at the time of the crime to a
preponderance of evidence.
Example of Guilty but Mentally Ill
Review the example with Jolene in Section 1. In this example, Jolene has been diagnosed with paranoia,
but shows an ability to control and understand the wrongfulness of her conduct, so she probably will
not be successful with an irresistible impulse insanity defense. If Jolene is in a state that offers a guilty
but mentally ill verdict, Jolene may be an appropriate candidate because she was mentally ill at the time
she assaulted and battered her sorority sister. If Jolene is found guilty but mentally ill, she will be
treated for her mental health simultaneously while serving any prison sentence.
152 CRIMINAL LAW
F I G U R E 6 . 5 Effects (Circular Diagram) of Mental Competency Claims
CHAPTER 6 CRIMINAL DEFENSES, PART 2 153
F I G U R E 6 . 6 Diagram of the Insanity Defense
154 CRIMINAL LAW
The defendant was insane
when the crime was
committed, but later
Hasan Fort Hood Shooting Video
Does Hasan Have an Insanity Defense? The Judge Rules!
In this news story on the legal implications of the Fort Hood shootings, Judge Napolitano discusses the up-
coming prosecution of Nidal Hasan and the possibility of an insanity defense.
1.9 Disposition of the Legally Insane
The not guilty by reason of insanity verdict means that the defendant is absolved from criminal re-
sponsibility and devoid of any criminal record for the offense. However, it does not mean that the de-
fendant is free to return to society.
In several states and federally, a defendant who is found not guilty by reason of insanity is auto-
matically committed to a treatment facility until there is a determination that mental health has been
restored. This is also the Model Penal Code approach. As the Model Penal Code states in § 4.08(1),
“[w]hen a defendant is acquitted on the ground of mental disease or defect excluding responsibility, the
Court shall order him to be committed to the custody of the Commissioner of Mental Hygiene [Public
Health] to be placed in an appropriate institution for custody, care and treatment.”
Other states have a hearing on sanity after the judgment or verdict of not guilty by reason of insan-
ity is returned. If the defendant is deemed mentally competent at the hearing, he or she is released. If
the defendant is found mentally ill at the hearing, he or she is committed to the appropriate treatment
1.10 Temporary Insanity
Many states also …