In criminal law, necessity may be either a possible excuse or an exculpation for breaking the law. Defendants who seek to rely on this defense argue that they should not be held liable for their actions as a crime, a tort or other form of unlawful act since the actions were urgently necessary to avert the threat of physical injury, or loss and damage. Most common law and civil law jurisdictions treat this defense with great caution and apply it only in very limited situations. Where a criminal defendant asserts necessity as a defense to murder, the analysis can be highly controversial. For example, consider the following two situations involving a police officer causing the death of an individual intentionally:

• An officer, having a good-faith reasonable belief that a person is a terrorist about to detonate a bomb in a public place, shoots and kills that person. The officer is correct, and this act saves many innocent lives.

• An officer, having a good-faith reasonable belief that a person is a terrorist about to detonate a bomb in a public place, shoots and kills that person. Upon investigation, the person turns out to be an entirely innocent individual mistaken for a terrorist.

In the former case, the law may consider this a justifiable homicide and excuse the officer from liability on the ground of necessity. In the latter case, the law may hold that the belief in the necessity of the action, no matter how reasonable, should not be enough to exculpate the culpability attaching for a death caused intentionally if the action does not, in fact, avert a greater harm. In some jurisdictions this is the rule of law.

The controversy is generated by the fact that both officers honestly believe that the killing is justified as necessary but one is excused from liability because, by chance, the threat is real, and the other is denied the defense because his or her honest belief proves to be wrong. The argument is that there should be no distinction between them based on the wisdom of hindsight. Either they should both be liable or they should both be excused. Some jurisdictions that allow the defense adopt a reasonable belief standard.

General Discussion

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As a matter of political expediency, states usually allow some classes of person to be excused from liability when they are engaged in socially useful functions but intentionally cause injury, loss or damage. For example, the fire services and other civil defense organizations have a general duty to keep the community safe from harm. If a fire or flood is threatening to spread out of control, it may be reasonably necessary to set fire to other property to form a fire break, or to trespass on land to throw up mounds of earth to prevent the water from spreading. At a less serious level, those who drive an ambulance to hospital on a grave medical emergency may deserve some latitude in exceeding the speed limit or ignoring red traffic lights. These examples have the common feature of individuals intentionally breaking the law because they believe it to be urgently necessary to protect others from harm, but some states distinguish between a response to a crisis arising from an entirely natural cause (an inanimate force of nature), e.g. a fire from a lightning strike or rain from a storm, and a response to an entirely human crisis. Thus, parents who lack the financial means to feed their children cannot use necessity as a defense if they steal food. The existence of welfare benefits and strategies other than self-help defeat the claim of an urgent necessity that cannot be avoided in any way other than by breaking the law. Further, some states apply a test of proportionality. So the defense would only be allowed where the degree of harm actually caused was a reasonably proportionate response to the degree of harm threatened. This is a legal form of Cost-benefit analysis.

Specific Jurisdictions

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England

For the main discussion, see necessity in English law''

Canada

Canadian criminal law allows for a common law defence of necessity. The leading case for the defence is Perka v. The Queen ^* 2 S.C.R. 232 in which Dickson J. described the rationale for the defence as a recognition that:

a liberal and humane criminal law cannot hold people to the strict obedience of laws in emergency situations where normal human instincts, whether of self-preservation or of altruism, overwhelmingly impel disobedience.

However, it must be "strictly controlled and scrupulously limited." and can only be applied in the strictest of situations where true "involuntariness" is found. Three elements are required for a successful defence :

1. the accused must be in imminent peril or danger
2. the accused must have had no reasonable legal alternative to the course of action he or she undertook
3. the harm inflicted by the accused must be proportional to the harm avoided by the accused

Each element must be proven on an objective standard. The peril or danger must be more than just foreseeable or likely. It must be near and unavoidable.

At a minimum the situation must be so emergent and the peril must be so pressing that normal human instincts cry out for action and make a counsel of patience unreasonable.

With regard to the second element, if there was a realistic or objectively reasonable legal alternative to breaking the law, then there can be no finding of necessity. Regarding the third element requiring proportionality, the harm avoided must be at least comparable to the harm inflicted.

In R. v. Latimer (2001), the Courts ruled that assisted suicide could not be excused by a defence of necessity.

United States

Model Penal Code

The Model Penal Code of the American Law Institute adopts a belief-based "choice-of-evils" theory of necessity in Section 3.02 - "Justification Generally: Choice of Evils":

§ 3.02 (1) Conduct which the actor believes to be necessary to avoid a harm or evil to himself or another is justifiable . . . .

The use of the defense is subject to certain limitations, notably: that the harm to be prevented be greater than that caused (§ 3.02(1)(a)); that it not be excluded by the law (§ 3.02(1)(b)) or a plain legislative purpose (§ 3.02(1)(c)); and that the actor not have recklessly or negligently have created the emergency, where the crime charged requires recklessness or negligence (§ 3.02(2)).

Note that the Model Penal Code is not the law of any state, though many states have adopted some of its rationale or provisions.

New York State

The Penal Law of the State of New York collapses justification and necessity into a single article. Article 35 - "Defense of Justification" comprises sections 35.05 through 35.30 of the Penal Law. The general provision relating to necessity, section 35.05, provides:

§ 35.05 Justification; generally. Unless otherwise limited by the ensuing provisions of this article defining justifiable use of physical force, conduct which would otherwise constitute an offense is justifiable and not criminal when: 1. Such conduct is required or authorized by law or by a judicial decree, or is performed by a public servant in the reasonable exercise of his official powers, duties or functions; or

2. Such conduct is necessary as an emergency measure to avoid an imminent public or private injury which is about to occur by reason of a situation occasioned or developed through no fault of the actor, and which is of such gravity that, according to ordinary standards of intelligence and morality, the desirability and urgency of avoiding such injury clearly outweigh the desirability of avoiding the injury sought to be prevented by the statute defining the offense in issue. The necessity and justifiability of such conduct may not rest upon considerations pertaining only to the morality and advisability of the statute, either in its general application or with respect to its application to a particular class of cases arising thereunder. Whenever evidence relating to the defense of justification under this subdivision is offered by the defendant, the court shall rule as a matter of law whether the claimed facts and circumstances would, if established, constitute a defense.

Under the "choice-of-evils" theory of section 35.05, it is a question of fact for the criminal jury whether the conduct was justified under the circumstances. See State of New York v. Maher, 79 N.Y.2d 978 (1992). As discussed in State of New York v. Gray, 150 Misc. 2d 852 (N.Y. Co. 1991),the defendant is generally held to a "reasonableness" standard--the question is whether a reasonable person in the defendant's position would have reached the conclusion that the relevant conduct was necessary. It is not necessary that the defendant actually avert a greater harm, just that his or her belief be reasonable. As the court observed:

To apply a strict liability standard in evaluating the other elements of this defense, however, and to find that only those actors who have actually averted a greater harm may avail themselves of the defense, is inconsistent with the law of justification in New York, as well as necessity's basic purpose to promote societal interests.

However, the defendant is subject to strict liability as to which harm is greater. For example, a defendant cannot choose to value property over life.

Similarly, when using physical force in defense of a person, the focus of the defense is not on whether the actor was in fact correct that his or her conduct was necessary to prevent harm, but whether that belief was reasonable. Section 35.15 (1) provides in relevant part:

1. A person may, subject to the provisions of subdivision two, use physical force upon another person when and to the extent he reasonably believes such to be necessary to defend himself or a third person from what he reasonably believes to be the use or imminent use of unlawful physical force by such other person . . . .

Thus, with respect to the example given above, the actor would, provided his or her belief was reasonable, be entitled to have a defense of justification presented to a jury.

It is important to distinguish between the defense of justification/necessity under Article 35 and the law of citizen's arrest. In general, to use physical force a private citizen must in fact be correct that a person has committed an offence, while a police officer must only have a reasonable belief.

References

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• Christie, The Defense of Legal Necessity Considered from the Legal and Moral Points of View, (1999) Vol. 48 Duke Law Journal, 975.
• Fuller, Lon L. The Case of the Speluncean Explorers, (1949) Vol. 62, No. 4 Harvard Law Review and The Case of the Speluncean Explorers: A Fiftieth Anniversary Symposium, (1999) 12 Harvard Law Review 1834.
• Herman, United States v. Oakland Cannabis Buyer's Cooperative. Whatever Happened to Federalism? (2002) Vol. 95, No. 1 The Journal of Criminal Law and Criminology, 121.
• Travis, M. The Compulsion Element in a Defence of Necessity (2000) ^*

Criminal defenses | Criminal law

Krajní nouze | Notwendigkeit | Estado de necesidad | 緊急避難 | Necessidade