Visit Our Blog
    Read Out Blog
    Case Evaluation
    Charged With A Crime?

    Understanding Defenses To Criminal Charges – A Brief Introduction To Criminal Law Defenses

    By Colorado Criminal Defense Lawyer  – H. Michael Steinberg for the Defense of Criminal Charges

    The Source of Law For Certain Defenses Against Criminal Charges

    Both State Laws and Cases decided by the Courts of Appeal – provide sources of laws that may be defenses to criminal charges. Other than having an alibi (which is not technically a defense but a denial), there are two main types of defenses:

    (1) Justification Defenses


    (2) Excuse Defenses


    …refer to situations in which the defendant doesn’t deny they did it but that they did it for all the right reasons, an appeal to higher loyalty or ideals (as in self-defense) or more important reasons (as in necessity).


    …refer to situations in which the defendant also doesn’t deny they did it but that they are not responsible for it (as in insanity or diminished capacity defenses), typically on grounds of lacking volition over their free will.

    Justifications often involve denying the mental state (mens rea). Where excuses involve denying the physical act (actus reus), but the mind-body connection is complicated in this regard… but it is less than crystal clear where these two interesect.

    Take sleepwalking, for instance, which might be treated as the inability to form mental intent although it’s the body (which is asleep). The law also tends to think of “mental” disorder as brain disorder, to avoid metaphysical debates over whether or not it’s possible for something invisible like a “mind” to get sick.

    This article divides the defenses to criminal charges into at least five different classes of defenses:

            • defenses that involve protecting competing interests; self-defense, defense of others, etc. where society excuses what would otherwise be a crime
            • defenses involving avoidance of a greater evil; necessity or duress, e.g., where society views the source of the predicament as coming from outside the defendant
            • defenses that attempt to disprove or negate mens rea; infancy, intoxication, mistake, and consent, 
            • defenses involving ignorance, where society recognizes that there might be sincere, genuine, and legitimate cases of not knowing the law or (naively) believing in something that negates an element of the crime.
            • defenses related to insanity, which may or may not be related to the variety of diminished capacity, stress-related, and domestic-related defenses.

    Justification Defenses

    The Self -Defense Defense

    Self-defense, or self-help, has always been a recognized justification, and it has many, many variations. It does not apply to preemptive strikes or paybacks, but it does cover a wide range of behaviors that make the crime seem justified, in fact, so justified that self-defense is called a perfect defense (the defendant “walks”).

    Other justifications and excuses may only be imperfect defenses which are treated as mitigating circumstances resulting in a lesser punishment.  Many of the various domestic violence defenses are examples of the defense of self-defense.

    The law of self-defense revolves around the notion of reasonableness. The person claiming it must have had a reasonable belief in imminent danger and used a reasonable degree of force. Some states have specifically mentioned self-defense can be used when the danger is a specific felony, such as rape, sodomy, kidnapping, and robbery.  Reasonable force means that if someone slaps your face and you shoot them, that’s unreasonable because you escalated force a bit too far when just returning a slap in the face might have been more reasonable. 

    Imminent is a word meaning in progress or about to happen right now. You can’t use self-defense for continuing and ongoing danger, although a few states have allowed this. Most states use an objective test to determine the sense of being imminent, and their statutes either spell out the grounds for a reasonable belief or they use a reasonable man standard. Other states use a subjective test (honest belief).

    Self-defense can include protecting family, friends, and lovers; i.e., in defense of others. Anti-abortion activists often claim this, but it’s more typically associated with things like the Mother Lion syndrome or some other so-called “emerging” defense to crime.

    The Public Duty Defense

    Another type of justification is a public duty defense. It’s the basis for a lot of military justice, diplomatic immunity, and covers a number of things that police do, such as shooting looters after a disaster. The idea here is that there’s a higher loyalty, and it’s located in upholding the law.

    A dilemma in law arises with the notion of resisting unlawful arrest. Why can’t citizens, for example, appeal to a higher duty when they think their arrest is unlawful?

    The Necessity Defense

    The principle of necessity is best explained by the prototypical case of cannibalism in the lifeboat. The famous case of The Queen v. Dudley and Stephans involved two men who ate a 17 year old weakly youth, after saying a prayer for him, because they were starving to death out in a lifeboat.  This is an example of the choice-of-evils defense the essence of which is in choosing the lesser of two evils or avoiding a greater evil (in the case of cannibalism, choosing to eat the weekly young man instead of letting the whole group starve). The MPC extends the necessity principle to include the following:

            • destroying property to prevent the spread of a fire
            • violating the speed limit to get a dying person to a hospital
            • throwing cargo overboard to save a sinking vessel and its crew
            • dispensing drugs without a prescription in an emergency
            • breaking & entering a mountain cabin to avoid freezing to death

    Economic Necessity – Another type of necessity defense is the claim to economic necessity. This would be stealing to avoid hunger, for example, but the classical dilemma is whether or not it would be right for a father to steal a loaf of bread to feed his starving children. Conflicting opinions can be found in the law and it’s approach to this problem.

    The extremely powerful and influential Commentaries (by Sir William Blackstone) for example state flatly that economic necessity is no defense. The Anglo-American approach has therefore been that the state’s power of pardon is enough to deal with poor people who commit crime out of need, so it would depend on case law and judicial opinion in a specific jurisdiction if this kind of defense would be successful.

    The Consent Defense

    Courts tend to recognize the defense of consent when people exercise their autonomy and choose to die or inflict injuries on themselves. The defense cannot be used if someone has solicited or authorized someone else to inflict injuries on them. This defense can be used in cases where two people are engaged in a consensual attack with one another (e.g., “fighting”), cases of injuries in sporting events, and cases in which emergency medical care had to be given which resulting in more harm than good. Condonation (forgiveness) by the victim and negligence by the victim are not generally considered as defenses.

    The Excuse Defenses

    The Duress Defense

    The main type of excuse is the defense of duress. The principle is that when people are forced to do something wrong, it ought not to count against them. There is widespread disagreement, however, over how duress is defined and what kinds of crimes can be excused by duress. States differ. Some permit only having a gun pointed to your head; others permit threats of bodily harm (“I’ll hurt you if you don’t do that”); and still others are fairly lenient is permitting such things as “If you don’t do that, I’ll tell other people something nasty about you”.

    Whatever the threat, it must be immediate, not some ongoing situation of extortion or blackmail. And, whatever the threat, the crime must be minor and not serious. Murder, for example, can never be excused by duress.

    Some modern forms of duress statutes have included the specific defense of brainwashing, a type of duress involving breaking down somebody’s will. If a person is confined, pressured for months, given hypnotic drugs, narcotics, or other substances, the law looks upon and crime committed under these circumstances as lacking the element of actus reus.

    The Intoxication Defense

    There are different ways to get intoxicated, and the law recognizes two ways: voluntary and involuntary. Voluntary intoxication goes to the element of mens rea (ability to form the capacity to understand purpose or intent), and is logically a justification. Involuntary intoxication, on the other hand, is an excuse because the person’s body did not know it was under the influence. There’s also an assumption of duress with involuntary intoxication.

    It’s not that one would have had to been held down and had the liquor poured down them by force (it’s almost like that if say someone insists you drink with them), but it’s more like a friend tells you to try out these sugar pills and they turn out to be LSD so you think someone looks like a rabid dog and you shoot them. Theoretically, the principle of intoxication gets at the concept of volition. Sometimes, it’s argued that watching television too long is a form of intoxication.

    The Mistake Defense

    Mistake or ignorance of fact has always excused criminal responsibility under some circumstances, and in all circumstances, it’s always acceptable that anyone holding a genuine and sincere belief in something which (if true) would negate their criminal liability should be something that does. The principle of mistake of fact excuses when it negates a material element in the crime. For example, taking the wrong umbrella when leaving the room because it resembled your own umbrella negates the element of mens rea (forming criminal intent to steal).

    The principle of mistake of law (ignorance of the law) excuses criminal behavior if a person has made a reasonable effort to learn the law. In practice, it’s difficult to distinguish between mistakes of fact and law, and the law must be careful to not open the door to allowing everybody to claim ignorance.

    Infancy As A Defense

    This is one of the three I’s (Intoxication, Infancy, and Insanity) that make up the capacity defenses to crime. The principle is that age always affects criminal liability. At common law, under age 7, there’s an irrebuttable presumption that someone is incapable of committing a crime. Under age 14, there’s a rebuttable presumption that someone is incapable of committing a crime. Changes in juvenile law and the increasing practice of waivers to adult court have substantially changed this common law, however, as society seems increasingly ready to recognize that young people can, and do, commit serious crimes.

    The Entrapment Defense

    Entrapment is a perfect defense (the defendant “walks”), but it’s often just a way to shift the burden of persuasion to the prosecution. It’s not a constitutional right. It’s a 20th Century invention that has it’s origins in sympathy for the accused. The principle, if there is one, of entrapment is that there’s limited sympathy because of the need to balance the needs of law-abiding citizens. It also depends on the crime. The law looks negatively at police entrapment in cases of consensual, victimless crimes. In order for entrapment to occur, police must initiate the encouragement of crime, specifically by any of the following: 

            • enticing suspects to commit crimes they would not otherwise commit
            • communicating the enticement to suspects and then influencing the decision to commit crimes
            • making repeated requests to commit a crime and then promising benefits from committing the crime
            • supplying essential materials and/or contraband to complete the crime

    A variation of the entrapment defense is Outrageous Government Conduct. In this case, the focus is on the government rather than the mind of the defendant. The principle is that when government behavior is so offensive and so outrageous, it cannot be the basis for collecting evidence to convict a suspect. Examples might include police infiltration and instances of undercover policing involving romantic liaisons.

    The Insanity Defense

    The insanity principle bestows upon the government the authority to incarcerate without conviction people who are abnormal and not average, everyday criminals. The defense is usually only seen when the crimes are very serious and the punishment quite severe. A successful insanity defense is not about going free (“walking”) but quite the opposite. Insanity impairs mens rea but it operates by affecting the brain (the body) via a mental illness. This is sometimes expressed as Insanity being a legal concept and mental illness a medical condition. The law reserves the right to not have to conform its definitions to those of the medical community, and to treat the whole issue of cureability as irrelevant. Insanity is an affirmative defense — the defense has to prove it if they raise it, but in practice, whomever brings up the issue first in court has the burden of persuasion. Over the years, various tests have been used to determine insanity, including:

    M’Naghten rule, or right-wrong test — focus is on the intellectual capacity to know right from wrong, pure intellectual awareness, cognition, being able to grasp the act’s true significance, not just a feeling or emotional sensation that something’s wrong.

    The Irresistible Impulse test — a revised type of M’Naghten rule in which the focus in on volition, whether the defendant exercised any free will in an attempt to inhibit their criminal behavior, or if they suffered from a “disease of the mind” so strong that they suddenly lost the power to avoid doing the act. If the crime was the product of a mental illness itself, this is considered satisfaction of the Durham rule.

    The Substantial Capacity test — a focus on the loss of “substantial”, not “total” mental capacity; the majority test in most jurisdictions because it is recommended by the MPC and conforms to the ALI (American Legal Institute’s) definition as “if at the time of such conduct as a result of mental disease or defect, he lacks substantial capacity either to appreciate the wrongfulness of his conduct or to conform his conduct to the requirements of law”. It substitutes the word “appreciate” for “knowing”, and allows for the possibility of affective or emotional understanding. The phrase “conform his conduct” is intended to replace the idea of “suddenness” in other tests, and the code’s definition of “mental disease or defect” excludes antisocial personality disorders, psychopaths, and sociopaths.

    The Automatism Defense –This is the preferred defense, instead of insanity, whenever it is claimed the defendant acted unconsciously or semiconsciously either due to a physical problem (epilepsy, concussion, or unexplained blackout) or mental problem (childhood trauma, mental things other than insanity, intoxication, and brainwashing).

    Diminished Capacity As A Defense

    These are syndromes that are always emerging, but in general, are perhaps best exemplified by the various stress and stress-related disorders. The principle of diminished capacity is that there are some mental diseases and defects that do not affect people sufficiently enough to make them insane, but the law recognizes them nonetheless. The law has really backed itself into a corner because it reserved the right to depart from definitions of the medical community, so all so all sorts of “legal diseases and defects”, so to speak, are possible.

    Other Articles of Interest:

    If you found the information provided on this webpage to be helpful, please click my Plus+1 button so that others may also find it.

    H. Michael Steinberg Esq.
    Attorney and Counselor at Law
    The Colorado Criminal Defense Law Firm of H. Michael Steinberg
    A Denver, Colorado Lawyer Focused Exclusively On
    Colorado Criminal Law For Over 40 Years.
    The Edward Building
    8400 East Prentice Ave, Penthouse 1500
    Greenwood Village, Colorado, 80111
    E-Mail:  [email protected]
    Primary Web Site:
    Colorado Criminal Law Blog:
    Main:  303.627.7777
    Cell:  720.220.2277
    24/7 Pager:  303.543.4433
    FAX (Toll Free):  1.877.533.6276
    Always investigate a lawyer's qualifications and experience before making a
    decision to retain that lawyer or, for that matter, any professional any field.