When most people think of criminals, they imagine hardened thugs who knowingly break the law. The modern media often shows real or imaginary situations where criminals have a clear motive and the means to commit an unlawful act. These are all examples of cut-and-dry cases of criminal intent, the kind that criminal law professionals work with every day.

However, criminal responsibility is not so clear-cut in many cases. In fact, in some instances, a person may commit a crime without having the capacity to understand that they’re doing something wrong. This is a quirk of the criminal mind, a complex topic that legal scholars have debated for centuries. This blog post will explore the legal definition of responsibility and discuss how the complexities of the mind affect individual cases.

Understanding the Criminal State of Mind

The core concept of any legal action is criminal accountability/responsibility. This term signifies the legal obligation of a person to answer for their crimes. It covers the individual's responsibility to be aware and comprehend their actions and thought process at the time the crime occurred. 

For any action to be considered criminal, the wrongdoer must have had the criminal state of mind, or "mens rea," when the act was committed. This means they must have intended, recklessly caused, or negligently caused the criminal act. The Model Penal Code (MPC) offers a similar definition.

Mens rea (mental state) is one of the oldest concepts in criminal law, and is crucial in helping define criminal responsibility. There are many different opinions as to what it entails. Some legal scholars argue that a person must have had a specific intent to commit a crime. Others believe that any mental state that leads to unlawful conduct can be considered mens rea.

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

The Criteria for Criminal Responsibility Evaluation

Several types of mens rea are crucial in proving a person's action to be unlawful: intention, recklessness, negligence, and strict liability.

  • Intention is defined as wanting to commit a crime and having the necessary means to do so. It's a willful engagement in the conduct or awareness of actions producing a specific result. For example, if a perpetrator uses a heavy and sharp tool to break open a window, enter a house, and steal the valuables inside, they have intentionally committed a criminal act of burglary. In general, crimes performed with such intent tend to have more severe punishments and can even incur the death penalty in the eyes of the law, criminal intent, and criminal responsibility.
  • Knowing is defined as being aware of the risks associated with a criminal act but deciding to do it regardless. A person who is conscious of online piracy yet still downloads and distributes copyrighted content is acting knowingly.
  • Recklessness is defined as consciously ignoring a risk or harm that the subject's actions will cause. If someone inappropriately uses a gun, such as pointing it at people instead of the ground, with the safety trigger off, that person has shown recklessness.
  • Negligence is defined as not taking reasonable steps to avoid causing harm. In this mental state, the actor is not consciously aware of the obvious dangers or risks their action will create, but a reasonable person would be, and this is all part of determining criminal responsibility. Harming a pedestrian by driving a car through a red light at a busy intersection while rushing to get to work on time is considered negligence.
  • Strict liability is when a person is held criminally responsible for an act even if they did not have any intent to commit a crime. In such cases, the defendant is found responsible for committing an illegal action, regardless of their mental state or intent. This is usually for minor offenses. In the USA, drug possession falls under strict liability, whether the subject was aware they were carrying an illicit substance or not.

Additional Criminal Law Situations

It's not enough to establish universal responsibility in criminal justice or criminology. Some additional conditions must be fulfilled in order for someone to be found criminally responsible.

  • There is no legal justification for the action, even if there might have seemingly been a “necessity” to commit it.
  • The subject is not excused from criminal responsibility because of specific personal characteristics. This includes a lack of mental capacity to comprehend that their action was criminal in nature.
  • There are no additional statute grounds that make the act noncriminal, such as a police officer's authority to employ force during the arrest of criminal suspects.
  • The individual cannot avoid the assessment of criminal responsibility by proving the act was lawfully justifiable. This may introduce complete defense when the criminal charge is null and void in its entirety, including inter-related offenses. Self-defense, property defense, defense of others, and necessity are examples of this criminal law situation. 

Defense Factors

There are a few defenses to criminal responsibility from a criminal act that can be used in court. 

  • Insanity is when the defendant could not understand the difference between right and wrong due to a mental illness at the time when the crime was committed. This mental state may prevent the person from understanding their actions or knowing that their activity is criminal, or it may cause them to act on ungovernable impulse. In this case, criminal charges may not always be dropped, but they could be reduced, along with the removal of specific intent-crime elements. The court recognizes criminal responsibility and insanity through several tests. 

The M'Naghten rule informs us that a person who cannot understand their actions or tell right from wrong is legally insane. The Durham rule applies when a mental defect was the cause of the criminal act. The Model Penal Code test of criminal responsibility says that the defendant who couldn't understand the criminality of their actions or act legally due to a diagnosed mental defect is considered insane. Lastly, the irresistible impulse test applies when a criminal act perpetrated by the defendant is the result of a lack of control over their impulses caused by a mental disease.

  • Severe intoxication can affect a person’s state of mind enough to contribute to the criminal responsibility defense of an actor by compromising their ability to act knowingly. There are two categories of intoxication: voluntary and involuntary.
  • Incompetence refers to a person’s inability to comprehend the legal proceedings and take an active approach in defending themselves. It’s one of the grounds for defense.
  • The public authority of an actor can protect them from being found responsible for the criminal act. National or regional public advisory bodies or individuals who conduct administrative duties under national law fall under public authority. This also includes someone who acts under the incorrect belief that the government authorizes their actions.
  • Self-defense and imperfect self-defense states that people may use force or deadly force to protect themselves against impending physical harm or threat and be considered exempt from criminal responsibility. Perfect self-defense is when the defendant uses a level of force proportionate to the threat faced. Imperfect self-defense is primarily used in attempted murder and murder cases to avoid sentencing or punishment by exhibiting that the guilty party had the unfounded or unreasonable belief they were facing a deadly threat.
  • Necessity is defined as an illegal act perpetrated during an emergency situation to stop something worse from happening. In this case, the actor must have the reasonable belief that there was a present and unavoidable threat that could only be stopped by their unlawful action. As a result, the act of necessity mustn't be worse than what would have occurred otherwise. Among the other legal criteria for avoiding criminal responsibility in this situation is that the defendant’s actions must not have caused any danger.
  • Consent is used as a defense in cases where the victim could reasonably expect the potential for certain types of bodily harm, such as practicing a heavy-contact sport.
  • Duress is when a defendant is forced to commit a crime because of enduring physical force or imminent threat of grave bodily harm done by another party. The defendant must have believed that the perpetrator would carry out the threat, and they must not have had an opportunity to escape.
  • Entrapment is when someone is forced or tricked into committing a crime by coercion or harassment from a government official. To mitigate ​​individual criminal responsibility, the defendant must prove that the original intent for their crime came from a government official, such as a federal agent or an undercover policeman. They must also prove that they didn't intend to conduct a criminal act before being approached by the government official.

Cases Involving Dementia and Neurodegenerative Diseases

One more thing legal professionals must consider when assessing whether someone is criminally responsible is the possibility that the person has a neurodegenerative illness, potentially related to their age. A study from Sweden shows that 42% of elders diagnosed with dementia exhibit signs of criminal or socially unsuitable behavior. This study of criminal responsibility for the elderly also revealed that 14.9% of Alzheimer's disease patients show signs of criminal behavior.

Courts have to prove that defendants with dementia are competent enough to understand their criminally responsible actions and stand trial. Neurodegenerative diseases can cloud judgment, which can lead to violent behavior, a lack of self-awareness, and poor emotional processing. As a result, law institutions cooperate with lawyers, free legal counselors, medical professionals, and patient representatives to assess whether an elderly defendant is criminally responsible.

Evaluation of Criminally Responsible Actions

For a person to be responsible for criminal actions, a criminal justice professional such as a  judge, or a committee like a jury, needs to decide that all elements that make up a crime are present. The evaluation of intellectual disability and criminal responsibility begins with two factors:

  • Police officers show objectively reasonable suspicion by detaining a suspect, investigating a possible crime, then arresting the suspect.
  • Judges analyze police actions, including arrests, based on probable cause before issuing an arrest warrant for a suspect. In return, police officers have to show that the objective circumstances justify the arrest.

Standard of Proof

The government has to prove every crime element beyond a reasonable doubt. This includes providing convincing evidence against the suspect that a reasonable individual wouldn’t doubt. The standard of proof has to be logically explicable, with the only possible outcome being that the suspect committed the crime.

The crucial element of international criminal responsibility is the intent:

  • Specific intent states that the crime was perpetrated knowingly, purposely, and willingly. When an actor shoots from a gun they thought to be a toy, the defense can claim that the suspect did not intend to shoot anyone.
  • General intent states that merely committing a criminal action signals the suspect's intention to commit a crime, including illegal mischief. For example, someone can claim that they set a building on fire, but they did not intend to destroy it. However, the action of starting a fire is enough evidence of general intent to show that the suspect was an arsonist.

Crimes With Specific Intent

With the following crimes, criminal responsibility, by definition, deals with specific intent:

  • A robbery is the unlawful seizure or theft of someone else's property, either by force or threat. When an armed perpetrator impounds the property while threatening victims with a weapon, that is called armed robbery.
  • A burglary is an act of unlawful entry into the building with criminal intent, such as larceny or theft. 
  • A conspiracy is an agreement between two or more parties to conduct a criminal act. They must be intent on completing the illegal goal and take preliminary steps to accomplish this. However, conspirators can be convicted of this crime without running any other criminal activity.
  • Murder is the act of unlawfully taking an individual's life with malicious second thought; it’s one of the most serious types of criminal responsibility. This malicious afterthought includes forming an intention of killing the person before committing to the criminal act. There are several levels of murder.

First-degree murder states that the killing was premeditated, willful, and deliberate. Second-degree murder is an intentional act that was not premeditated, including murder conducted under the heat of passion. Third-degree murder is the unintentional yet perpetrated act of taking a life while committing other intentional crimes, such as armed robbery. 

The felony murder rule says that if a suspect conducts a crime and someone else dies as a result, that suspect can be charged with murder in criminal responsibility cases. For example, if a perpetrator is involved in a crime where one of their partners shoots an innocent bystander to death, they may be charged with murder even though they didn’t pull the trigger. 

Crimes With General Intent

There are some acts of crime that include general intent:

  • Manslaughter is the unlawful killing of an individual without malicious second thought. It can be voluntary manslaughter, also known as a crime of passion before the suspect had the time to "cool off" or gather their thoughts. Involuntary manslaughter is known as criminally negligent homicide or unintentional homicide, resulting from a reckless action that ends in unintentional killing.
  • Arson is the malicious and wilful burning or extensive charring of a property with criminal responsibility. It can include any intentional burning of someone else's property, including starting a forest fire or burning a building to fraudulently and illegally collect an insurance payment.
  • Assault is an intentional and imminent action that involves offensive or harmful contact, or close proximity that could bring about a reasonable fear of contact in the victim. Aggravated assault includes the usage of a deadly weapon.
  • Battery is a finished assault, which courts once charged as a separate crime. It is now combined in most jurisdictions as the crime of assault and battery.

Lowest Age of Criminal Responsibility

The US federal government recognizes juveniles as anyone under 21 when criminal proceedings start, and they must be held responsible for violating a federal law before their 18th birthday. Prosecutors and federal agencies tend to move juvenile cases to state courts as much as possible.

However, the minimum age that someone can be held criminally responsible depends on the state. In 28 states, there is no such minimum age requirement. In contrast, specific federal laws and 22 states have set the minimum age for criminally responsible intent between six and 11 years old. 

Massachusetts raised the minimum age from seven to 12 years old in 2018. California sets the minimum age for the evaluation of criminal responsibility at 12, except for specific violent crimes that have no minimum age requirement. Children may be criminally charged, regardless of their age, if they have the right presence of mind to be deemed competent and understand the criminal nature of the acts they’ve committed.


The criminal mind is a multilayered topic that legal scholars have debated for centuries. In this blog post, we’ve only scratched the surface; after all, criminal responsibility is a complex issue that requires a detailed understanding of the law. Hopefully this article has helped begin to answer the question “what is criminal responsibility?” and given you some ideas about where to go from here.