Why Necessity Is a Justification

Why Necessity Is a Justification

The question left open above has a precise answer, and it determines how every later element of § 3.02 should be read. A defendant who raises necessity admits having done what the offense forbids, and admits having done it on purpose. The claim is that, in the circumstances, the deliberate act was the right one to take. In the forest-fire case the actor burns the cornfield with the purpose of destroying it, so every element of arson is met, and the loss of the field is the very harm the arson statute exists to prevent.¹ A justification leaves that harm on the books as a legally recognized harm to be avoided whenever possible, and holds only that in the special circumstances it is outweighed by the need to avoid a greater one.²

The reason the law tolerates such conduct comes from the purpose of the prohibition itself. A criminal prohibition exists because it protects some value, such as property or life, and when literal obedience would destroy a more important value, strict compliance defeats the very purpose the prohibition serves. The law therefore prefers the lesser evil. A starving person who takes another's food has given up a property interest to save a life, and an actor who kills one person to save two has produced one death where compliance would have produced two. The law forbids stealing and killing because property and life are worth protecting, yet it is better to save a life than property and better to lose one life than two.³ The same logic can be put in the defendant's own mouth. One who breaches a dike to save a town, knowing the water will drown the occupants of a farmhouse, can answer a homicide charge by pointing out that the law of homicide exists to save life and that the breach produced a net saving of innocent lives.⁴ The defense thus draws its force from the offense's own purpose.

Because the actor chose the conduct, the rationale for necessity does not depend on any missing mental element. It rests on a public-policy judgment that the law should promote higher values at the expense of lesser ones, even when that means departing from the literal words of the offense.⁵ Students often misplace the defense by treating it as an argument that the actor lacked purpose or knowledge, but necessity does not negate the mental state the offense requires. The actor who burns the field has exactly the purpose arson demands and is still justified. Smaller emergencies work the same way. Donald, charged by a raging bull, hits it with Victoria's Ming vase, destroying the vase but diverting the bull, and if he is charged with intentional damage to her property his argument has to be necessity, the choice of the lesser of two evils.⁶ Beside him stand Ken, who steals a lawn mower under a threat of death and would argue duress, and Ebenezer, who faces what looks like a machine gun and would argue self-defense; the common law treated all three as instant decisions in dire conditions but gave each its own doctrine.⁷

Calling necessity a justification also places it on one side of a distinction the law draws between two kinds of defense. A justification says the conduct was rightful in the circumstances, while an excuse admits the conduct was wrongful and says the actor should nonetheless go unpunished; self-defense and a police officer's use of force are the usual examples of the first, and insanity and mistake of fact of the second.⁸ The label matters because it fixes what the defense examines. A justification examines the act and its consequences, asking whether the world was better for the choice, whereas an excuse examines the actor, asking whether this person can fairly be blamed. The Supreme Court of Canada in Perka v. The Queen took the second path for its residual necessity defense. It treated the defense chiefly as an excuse for acts compelled by pressure so overwhelming that the actor had no real choice, and it voiced wariness of a broad utilitarian justification because that would let individuals and judges decide when to disregard statutes and could become a "mask for anarchy."⁹ That decision is a point of contrast only. Model Penal Code § 3.02 sits in the Code's Article on justification and declares qualifying conduct "justifiable."¹⁰ Its test is an objective comparison of harms, which applies when, viewed from an objective perspective, the harm caused by breaking the law is less than the harm avoided.¹¹

One further boundary keeps the defense tied to choice. For necessity, the pressure of circumstances must operate on the actor's mind rather than on his body.¹² If A and B stand atop a precipice and an earthquake makes A stumble against B so that B falls to his death, A has no necessity defense to homicide, because A's mind never willed the movement. His defense is that he performed no act at all, since a crime of action requires a willed movement.¹³ Change one fact and the analysis changes: if A, starving, takes and eats B's food, or if A in an emergency intentionally kills B to save C and D, A's mind has chosen the conduct and he may be eligible for the defense.¹⁴ A justification is a verdict on a choice, so it presupposes that the actor made one.

Two provisions of Article 3 then govern how a justification operates in a prosecution. Section 3.01(1) makes justification an affirmative defense, meaning the defendant must put it in issue by asserting facts that make the conduct justifiable even though the offense's elements are met.¹⁵ Who must then persuade the factfinder varies by state, because a legislature may place on the prosecution the burden of disproving any defense the defendant has properly raised.¹⁶ Section 3.01(2) adds that justifiable conduct does not abolish or impair any remedy for that conduct available in a civil action.¹⁷ The reason follows from the nature of a justification: the harm remains a recognized harm, so someone has still lost something. The owner of the burned cornfield, whose crop was sacrificed to save the town, is therefore left where civil law would otherwise leave him, because the actor's acquittal says nothing about whether the owner has a civil claim.

Courts nonetheless apply the defense narrowly, and the explanation lies in what a successful claim accomplishes. Judge Amul Thapar explained in United States v. Walli that the defense involves a cost-benefit analysis in which the defendant admits breaking the law but says the choice achieved the greater good. A successful claim therefore "implicitly amends the criminal code" to carve out the defendant's actions, and a broad version would trump the decisions of the elected legislature, the branch best suited to such utilitarian judgments.¹⁸ The Code's Comment states the same point more gently, describing the defense as an interpretation of the law of the offense, on the premise that the special situation calls for an exception the legislature could not reasonably have intended to exclude.¹⁹ The two descriptions converge on a practical rule. The defense is strongest where the emergency and the balance of harms are so clear that the legislature would plainly have wanted the exception, and it must yield where the legislature has actually spoken, which is the work of § 3.02(1)(b) and (c).²⁰ Before those limits, though, comes the question of how far the older common-law defense reached and where the Code departs from it, which the next section takes up.