Criminal Law

XIV. Defenses to Crimes

The law recognizes that people engage in conduct that is considered criminal but that might be excused or justified because their mens rea was negated or society excuses their conduct. These justifications and excuses are defenses to criminal offenses. The U.S. system places the burden of proof upon the government to prove the charges beyond a reasonable doubt. The defendant is presumed innocent until proven guilty. Moreover, as part of the criminal process, the accused is given an opportunity to present a defense. There are many types of defenses, from alibi to self-defense. Sometimes, the defense can be based upon the prosecution’s inability to prove the charge, or the defense can be a so-called affirmative defense where the defendant presents evidence and witnesses to disprove an element of the offense (Torcia, 1995).

A. Failure of Proof or True Defenses

When a defendant is on trial, she might rely upon the prosecution’s inability to prove the case against her. The accused might remain silent throughout the trial and have no duty to present any evidence. The defense might attack the government’s case through cross-examination or simply take the position that the government has failed to prove the case against her. These strategies rely upon a failure of proof for the defense (Greenwalt, 2002).

When the defendant actively presents evidence of an excuse or a justification, it is said that he is presenting a true defense. If a true or affirmative defense is established, the defendant is entitled to an acquittal, even if the government has proven all the elements of the crime against him. After the defendant has presented evidence of a true defense, the burden is on the prosecution to disprove the defense beyond a reasonable doubt. When a defendant relies upon an affirmative defense, he is admitting that there is a basis for criminal liability but is offering a legally recognized reason why he should still be acquitted. When an affirmative defense is used, the burden of raising the defense lies with the defendant. After the defense is raised, the burden of proof shifts back to the government, and the prosecutor must prove beyond a reasonable doubt that there is a lack of justification or excuse (Reitz, 2002). Suppose Fred walks into his home and finds his wife, Wilma, injured on the bedroom floor. He then encounters a burglar and kills him. Fred admits that he intentionally killed the burglar but insists that the killing was justified. The prosecutor must prove that Fred did not kill the intruder in self-defense. If the defense is accepted by the jury, Fred will be acquitted even though he admitted a homicide.

There are two general categories of affirmative defenses. Under a justification defense, conduct by the accused that is otherwise criminal is deemed to be socially acceptable and is not subject to punishment because of the circumstances of the case. This defense focuses on the nature of the conduct and the surrounding circumstances. Under an excuse defense, the defense focuses on the accused’s moral culpability and whether he possessed the mens rea (guilty intent) required to commit the crime. In such a case, society recognizes that the defendant has caused some social harm but agrees that he should be excused from blame or punishment (Frase, 2002).

The law permits self-defense (a) when you are not the aggressor, (b) when you reasonably believe it is necessary to defend yourself, and (c) to avoid an unlawful and imminent attack. Moreover, most states have adopted a rule that allows defense of another when it reasonably appears that unlawful force is being applied to the defended person by an aggressor. Note that the use of deadly force is appropriate only when a person must defend herself or another person in an effort to prevent imminent death or serious bodily harm (Garland, 2003).

When an aggressor uses any force to gain entry into a residence, the resident can stand his or her ground and use all force reasonably necessary to defend himself or herself. This is the so-called castle doctrine. In some states, reasonableness is presumed, and the resident can use deadly force whenever an aggressor enters his or her home by force. The force can be as simple as opening a door or window (Dressler, 2001).

Necessity is sometimes referred to as the lesser-of-two-evils defense. A person can avail herself of the necessity defense when the following conditions are met: (1) The person must be faced with a clear and imminent danger; (2) the greater harm must be the direct cause of the law violation; (3) the person cannot have a lawful legal alternative to the law violation; (4) the harm that the defendant causes by violating the law must be less serious than the harm she seeks to avoid; and (5) the defendant must come to the situation with “clean” hands—that is, she must not have wrongfully placed herself in a situation that requires the choice of evils (LaFave, 2003, p. 523).

In addition to the five requirements that show when a person is justified in violating criminal law, some states place three additional limitations on the use of the necessity defense: (1) The defense might be limited to situations created by natural forces—for example, looting a store might be a necessity following a hurricane or earthquake; (2) the defense does not apply to homicide case—a person cannot kill someone to save his own life; (3) the defense can be used only to protect persons and property, not to protect pure economic interests or personal reputation—a person cannot assault someone merely to protect his own honor (Frankel, 1993, pp. 138–139).

B. Defenses Based on Excuses

To assert a defense of duress, the defendant must admit that he committed the crime but did so under the following circumstances (all circumstances must be met): (1) Someone threatened to kill or cause great bodily harm to the defendant or a third party unless he committed the offense; (2) the actor reasonably believed that the threat was genuine; (3) the threat was present, imminent, and impending at the time of the criminal act; (4) there was no reasonable means of escape other than for the defendant to commit the crime; and (5) the defendant must not be at fault in exposing himself to the threat. However, it is important to note that duress is not an acceptable legal defense for murder (Perlin, 2002, p. 650).

The defense of infancy has been asserted for hundreds of years. Courts have recognized that children under a certain age were incapable of forming criminal intent. Today, states have set this age at anywhere from 10 to 14 years. Some states, such as California, allow for culpability under a set age of 14 if there is clear proof that at the time of committing the act charged against her, the child knew its wrongfulness. Oklahoma uses the same language but sets the age at 16. In addition to allowing prosecution in a juvenile court setting, most states allow juveniles to be prosecuted as adults when they have committed a violent felony and are a certain age. Some states set that age as low as 10, whereas others set it as high as 16. Juveniles tried as adults can be sent to prison (LaFave, 2003, p. 485).

Voluntary intoxication is not a valid defense for crimes that have a general intent. For crimes with a specific intent, voluntary intoxication can be used to negate the element of intent if the level of intoxication was so high “as to render [the accused] incapable of purposeful or knowing conduct” (Lafave, 2003, pp. 472–473). Several states have eliminated the defense of intoxication in its entirety. A jury is not allowed to consider evidence of intoxication. The judge can consider it only as a mitigating fact at sentencing. Involuntary intoxication is a defense if the jury finds evidence that both of the following happened: (1) The defendant did not voluntarily take the drug or intoxicant and was forced or tricked into taking it, and (2) the defendant was so intoxicated that he couldn’t form the requisite mens rea for the charged offense (Fingarette & Hassle, 1993, p. 742).

In many states, a defendant who has insufficient evidence to prevail on an insanity plea might still present evidence of a mental condition on the issue of whether he had the requisite mental state for the offense. This is a diminished capacity defense. This is not a true defense as much as it is a failure-of-proof defense that negates mens rea. However, diminished capacity can be used as a true defense in a murder prosecution to mitigate the offense to manslaughter. During the past 20 years, there has been a movement to abolish diminished capacity in several states (Garland, 2003).

The law recognizes that people are not criminally liable for acts committed when they are not sane at the time of the offense. Sanity is determined by the jury applying the irresistible impulse test, the substantial capacity test, or the so-called M’Naghten Rules. Four states have abolished the insanity defense altogether, while only four use the irresistible impulse test. A person is insane under this test if, at the time of the offense, (1) she acted from an irresistible and uncontrollable impulse, (2) she was unable to differentiate between right and wrong behavior, and (3) she did not have the will necessary to control her actions (Fingarette & Hassle, 1993, p. 744–746).

The substantial capacity test provides that a person is not responsible for her criminal conduct if, at the time of the conduct, as the result of a mental disease or defect, she lacked substantial capacity to do one or both of the following: (1) appreciate the criminality or wrongfulness of her conduct and (2) conform her conduct to the requirements of the law. The substantial capacity test has been adopted by just under half of the states (McClain & Kahan, 2002, p. 412).

Half of all states determine sanity by applying the M’Naghten Rules. A defendant is not legally responsible for his acts if at the time he was “laboring under such a defect of reason, from diseases of that mind, as not to know the nature and quality of the act he was doing, or if he did know, that he did not know that what he was doing was wrong” (Neubauer, 2008, p. 306).

In general terms, mistake of law is not a defense. If, however, a law is ambiguous and might prevent a reasonable person from knowing whether her conduct is prohibited by the statute, the defendant might have a defense against application of the law to her. This is actually a constitutional defense because an ambiguous law fails to meet the requirements of due process under the Fifth and Fourteenth Amendments to the U.S. Constitution (Chevigny, 2002).

A mistake of fact is a defense if it negates the mental state required to establish any element of the offense. If a defendant makes a mistake and takes the wrong coat from a closet at a party, his mistake negates the intent to steal that is necessary for a theft to have occurred (Chevigny, 2002).

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