Criminal Responsibility: Evaluation and Overview


The cornerstone of modern criminal law is that a person is presumed innocent until proven guilty for more detail Click here, whether through their own confession or a criminal proceeding. However, many factors come into play when determining whether a person who commits an illegal act is criminally responsible.

The criteria for determining whether a person bears criminal responsibility for a criminal act include the person’s competence, defenses, and whether the prosecution is able to prove all the elements of the crime. In certain situations, an action that would otherwise be deemed a crime may be lawful. Among the defenses, the accused can raise to avoid criminal responsibility are self-defense, necessity, intoxication, duress, mistake of law or fact, and mental incompetency.

Note that mistake of law is a defense against criminal responsibility in four specific circumstances: the law hasn’t yet been published, the law was later overturned or deemed unconstitutional, the judicial decision the defendant relied on was later overturned, or the defendant relied on an official’s erroneous interpretation of the law.

One of the most important responsibilities of the criminal justice system is to protect the rights of the accused, including their right to raise all potential defenses. Programs such as Maryville University’s online Bachelor of Arts in Forensic Psychology degree program prepare criminal justice professionals to participate in legal proceedings, whether on behalf of the defense or the prosecution, to help ensure that all defendants receive a fair trial.

Criminal responsibility definition: What does it mean to be criminally responsible?

Criminal responsibility is defined in the Model Penal Code (MPC) as occurring when a person commits a criminal offense with intention, recklessness, or negligence. The MPC was created by the American Law Institute as a guide for state governments to use when updating and standardizing their criminal statutes.

For any act to be considered a crime, the perpetrator must have had a criminal state of mind, or “men’s rea,” when the act was committed. If the person didn’t act with the intent in mind to break the law, or in a way that showed a reckless and willful disregard for the safety of others, then their act can’t be labeled criminal. However, even if the person wasn’t aware that their action was against the law, if they intended the action, then the person possessed the men’s rea required to be convicted of the crime.

In addition to proving that a person acted intentionally, recklessly, or negligently, several other conditions must be met for the person to be found responsible for a crime:

  • There is no legal justification for the act due to specific circumstances of the event, such as necessity.
  • The person is not excluded from criminal responsibility due to a specific characteristic, such as lacking the capacity to understand that the act was a crime.
  • There are no other grounds defined in a statute that render the act noncriminal, such as a police officer’s statutory authority to use force to arrest a criminal suspect.

An offense committed with intention, recklessness, or negligence

To establish criminal responsibility for an illegal act, the prosecution must prove that the person either acted with the intention of performing the act, or the person acted recklessly or negligently.

  • A person acts with intention when they do so purposely and knowingly.
  • A person acts with recklessness when they take risks that are objectively unjustifiable given the circumstances of the act that the person is aware of.
  • A person acts with negligence when they take risks that are objectively unjustifiable considering the circumstances the person is aware of, even if the person is not cognizant of all the risks involved.

In some instances, the MPC excludes a person from being criminally responsible for an illegal act if they acted recklessly or negligently. For these crimes, intent — whether specific or general — is a required element that prosecutors must prove.

There was no lawful justification for committing the offense

A person may avoid criminal responsibility for an illegal act if they can show that the act was justifiable. Justification is considered a complete defense because it may nullify the entire criminal charge, including interrelated offenses. Justification defenses include self-defense, defense of others, defense of property, and necessity.

There are no other grounds for excusing criminal responsibility

In addition to the defense of justification, a person can be excused from criminal responsibility for an illegal act if they can raise one of the following defenses:

  • Authorization (the Public Authority defense): A person’s public authority may allow them to avoid being found criminally responsible for an act. This defense also applies when the person acts with the mistaken belief that they are authorized by the government to take the action.
  • Incompetence: For a person to be found criminally responsible for an illegal act, they must demonstrate sufficient competence to understand the legal proceedings and to actively participate in their own defense.
  • Insanity: A person who commits a crime can avoid criminal responsibility for the illegal act if the court determines that they were legally insane at the time the crime was committed.
    • The person’s mental state may have prevented them from understanding what they were doing.
    • Their mental state could have kept them from knowing that what they were doing was a crime.
    • They may have acted as a result of an uncontrollable impulse.

How is the minimum age of criminal responsibility determined?

Rather than establish a minimum age at which children take criminal responsibility for their acts, the federal government identifies juveniles as anyone under the age of 21 at the time criminal proceedings would begin who violated federal criminal law before their 18th birthday. As much as possible, federal agencies and prosecutors direct all juvenile criminal cases to state courts, including violations of federal law.

The minimum age of criminal responsibility varies from state to state. In 28 states there is no minimum age of criminal responsibility established by statute, while 22 states and certain federal laws set a minimum age that ranges from 6 years old to 11 years old, with two exceptions:

  • In 2018, Massachusetts raised its minimum age of criminal responsibility from 7 to 12.
  • California has enacted a minimum age of criminal responsibility of 12 years old, except for specific violent crimes for which there is no minimum age of criminal responsibility.

An important consideration in determining whether children of any age can be charged with a criminal offense is whether they possess the required presence of mind to be declared competent from a legal perspective. If children are unable to appreciate the criminal nature of any illegal acts they commit, they lack the competence required to be found criminally responsible for the acts.

Reasons a person lacks competence

All criminal defendants must have been sufficiently aware of the criminal nature of their illegal actions for the court to determine that they were competent at the time of the offense. Examples of states of mind that may affect competence are gross intoxication and insanity:

  • Gross intoxication may be voluntary or involuntary. While the law is unsettled on this criminal defense, courts have determined that defendants’ ability to act knowingly and purposely can be impaired by gross intoxication.
  • Insanity as a criminal defense may not clear the defendant of all criminal responsibility for an illegal act, but it may mitigate charges and remove a required element of a specific intent crime.

Inability to understand and participate in the trial

Competency also relates to a person’s ability to comprehend the charges they face and to assist in their own defense. To be declared competent, defendants must meet several criteria:

  • They must be able to consult with their attorney and have some rational understanding of their legal options and strategy.
  • They must understand the nature of the charges they face and the evidence that may implicate them.
  • They must also be capable of entering a plea and comprehending the consequences of their plea in terms of loss of freedom and other potential punishments.

Criminal responsibility evaluation: How is a person found to be criminally responsible?

A person bears criminal responsibility for an illegal act only if the prosecution can prove to the trier of fact, whether a judge or a jury, that all elements of the crime were present. A criminal responsibility evaluation begins when criminal charges are initially filed:

  • Police officers are allowed to detain someone while investigating a possible crime only if they can show objectively that reasonable suspicion exists for pursuing the individual in their investigation and making an arrest.
  • Judges evaluate the arrests and other actions of police based on probable cause, which must be demonstrated before a judge will issue an arrest warrant for the suspect. This requires that the officers present objective circumstances that justify the arrest for the specific crime or crimes being charged.

Prosecutor’s burden of proof

To convict a person of a crime, the government must prove all the elements of the crime beyond a reasonable doubt. This means that the evidence against the defendant is so convincing that no reasonable person would question whether the accused is guilty. This standard of proof can be met only if there is no logical explanation or conclusion other than that the charged party committed the crime.

An important element of most crimes is intent.

  • Specific intent means the crime was committed knowingly, purposely, and willingly. For example, if someone shoots a person with a gun that they thought was a toy, the defense can argue that the person had no intention of shooting the person in fact.
  • General intent means that simply taking the criminal action implies the person’s intention to do so. An example is a person who sets fire to a building but argues that they did not intend to destroy the building. The act of starting the fire demonstrates sufficient intent to be convicted of arson.

Specific-intent crimes

Specific-intent crimes include the following:

  • Murder is defined as the unlawful killing of another person with malice aforethought. Malice aforethought means they formed the intention of killing the person prior to taking the action. Most jurisdictions have multiple levels of murder:
    • First-degree: The action was willful, deliberate, and premeditated.
    • Second-degree: The action was intentional but not premeditated, such as murders perpetrated in the “heat of passion.”
    • Third-degree: The action was unintentional but perpetrated in the course of committing some other intentional crime. In some jurisdictions, this crime is synonymous with manslaughter. However, the felony murder rule states that if a person commits a felony and someone dies as a result, such as an innocent bystander being shot to death, then the perpetrator can be charged with murder even if they were not directly involved in the shooting.
  • Robbery is the unlawful taking of the property of another by threat or force. Armed robbery is when the property is taken under the threat of bodily harm from a weapon wielded by the perpetrator.
  • Burglary is the unlawful entry into a building with the intent to commit a crime therein. The intended crime is often theft or larceny, but it can be any crime. No physical breaking into the building is required so long as the person is not authorized to enter.
  • A conspiracy is an agreement between two or more people to commit an illegal act. Conspirators must intend to achieve their goal and must take some preliminary steps toward doing so, but can be convicted of conspiracy without any other criminal activity occurring.

General-intent crimes

These are among the general-intent crimes:

  • Manslaughter is the unlawful killing of another without malice aforethought. The two primary types of manslaughter are voluntary and involuntary.
    • Voluntary manslaughter is often referred to as a “heat of passion” crime because it occurs in response to an incident that would have provoked a reasonable person. The crime must occur before the person has had time to “cool off.”
    • Involuntary manslaughter is sometimes called unintentional homicide or criminally negligent homicide because it results from reckless conduct that leads to an unintentional killing.
  • Arson is the willful and malicious burning or significant charring of a building or other property. Arson is often committed against a person’s own property to fraudulently collect an insurance payment, but it applies to any harmful intentional burning, such as a person who starts a forest fire.
  • Assault is any intentional act that puts another person in imminent fear of harmful or offensive touching. For example, a person who threatens another person with a club and is close enough to carry out the threat is guilty of assault even if no actual touching occurs: The crime occurs when the intended victim fears being attacked. Aggravated assault is an assault that occurs using a deadly weapon.
  • The battery is often referred to as a completed assault. In the past, assault and battery were charged as two separate crimes, but now most jurisdictions combine them into the single crime of assault and battery.

Defenses to crimes requiring the intent

These are among the defenses that a person charged with an intentional crime can raise to avoid being found criminally responsible:

  • Self-defense and imperfect self-defense: The law allows people to use force, including deadly force, to protect themselves from the imminent threat of physical harm. Courts require that the level of force used to defend oneself be comparable to the threat the person faced. This is sometimes referred to as “perfect self-defense.” By contrast, imperfect self-defense applies in murder and attempted murder cases to negate the element of intent required to convict by showing that the perpetrator had an unreasonable or unfounded belief that they faced a deadly threat.
  • Necessity: This defense can be raised when a person commits an illegal act during an emergency situation in an attempt to prevent something worse from happening. The person must have reasonably believed the threat was present and that they had no other options for stopping it. Also, the damage that results from the act cannot be worse than what would have happened otherwise, and the person cannot bear any responsibility for creating the dangerous situation in the first place.
  • Insanity: Courts use four different tests to determine whether a defendant is not guilty due to insanity.
    • The M’Naghten rule states that the person could not tell right from wrong or did not understand the consequences of their action.
    • The irresistible impulse test states that the illegal act resulted from a mental disease that prevented the defendant from being able to control their impulses.
    • The Durham rule states that the criminal act was a result of a mental defect of the defendant.
    • The Model Penal Code states that due to a diagnosed mental defect, the defendant was unable to understand that their actions were criminal or could not act in a legal manner.
  • Intoxication: This defense excuses the defendant from the criminal act because intoxication made them unable to understand the nature of their actions or know that the action was wrong. The intoxication can be voluntary or involuntary, but this defense applies only in a limited number of circumstances, and voluntary intoxication is never a defense to a general-intent crime.
  • Consent: Defendants raise this defense primarily in cases involving bodily harm, such as an injury that occurs while playing a physical-contact sport. The defense does not apply when serious bodily injury is involved, and the type of injury must be reasonably expected considering the nature of the activity the victim is said to have consented to. Also, the victim must realize some benefit from the type of contact that led to the injury for the consent defense to apply.
  • Duress: This defense may be raised when the defendant is compelled to commit a crime due to the threat or actual application of physical force by another. The defendant must have faced the imminent threat of serious physical harm, they must have had a reasonable belief that the person would carry out the threat, and they must not have had any escape available or other recourse. This defense never applies to the crime of murder.
  • Entrapment: When a defendant believes they would not have committed the crime but for the harassment or coercion of a government official, they may raise the defense of entrapment. To successfully assert this defense, the defendant must prove that the genesis of crime originated with a government official, typically an undercover police officer or federal agent. They must also show that they weren’t already willing and able to commit the crime prior to being approached by the government official. The burden of proving the entrapment is on the defendant.

Dementia and criminal responsibility

Researchers have been studying the connection between dementia and a defendant’s criminal responsibility for illegal acts that may have been influenced by the person’s diminished mental capacity. A study conducted in Sweden determined that 42% of people diagnosed with dementia due to frontotemporal lobar degeneration had exhibited criminal or socially inappropriate behavior. By comparison, only 14.9% of people diagnosed with Alzheimer’s disease had any record of behaving in criminal or socially inappropriate ways.

Dementia affects criminal responsibility for illegal actions because courts require that defendants be competent enough to understand that their actions were criminal. Defendants must also be competent to understand the proceedings, enter a plea, and participate in their own defense, including being able to clearly communicate with their attorney. Many people whose criminal acts were the result of their dementia testify that they understood that what they were doing was wrong.

The damage done by neurodegenerative diseases affects judgment, emotional processing, self-awareness, and disposition to violence. This may result in antisocial and criminal behavior in middle-aged and elderly people with no previous history of such behavior. The courts work with medical professionals, lawyers, and other patient representatives to determine whether a criminal defendant suffering from dementia possesses the necessary competency and mental capacity to face criminal responsibility for their acts.

Understanding the implications of criminal responsibility

The judicial system is dedicated to bringing criminals to justice following all laws and procedures. The prosecutor’s burden is proving beyond a reasonable doubt that a person bears criminal responsibility for their illegal acts. The defense cites reasons why the defendant is not criminally responsible.

This is the heart of the criminal justice system, and of the role of forensic psychologists in criminal proceedings. Preparing for a career as a forensic psychologist is the focus of programs such as Maryville University’s online Bachelor of Arts in Forensic Psychology degree program, which features courses in social psychology, criminal behavior, and criminological theory.

Learn more about how the Bachelor of Arts in Forensic Psychology program can help you gain the skills and experience required for a career as a forensic psychologist.