Introduction

Necessity and Choice of Evils

Introduction

A forest fire is racing toward a town of 10,000 people, and the only way to stop it is to burn the field of corn that lies between the flames and the houses. The burned field becomes a firebreak, and the town is saved. Nobody is attacking the actor, so self-defense does not fit, and the actor holds no office that commands the burn, so a public-duty justification does not fit either. Setting the fire on purpose still satisfies every element of arson, because the destruction of the field is exactly the harm the arson statute exists to prevent.¹ Even so, the actor is likely to have a complete defense, because society tolerates, and even encourages, this conduct when the alternative is the loss of the town.²

Model Penal Code § 3.02 supplies the defense for cases like this one. It makes justifiable any conduct that the actor believes necessary to avoid a harm or evil to himself or to another, provided that the harm avoided is greater than the harm the law defining the offense seeks to prevent, that neither the Code nor other law defining the offense provides exceptions or defenses for the specific situation, and that no legislative purpose to exclude the justification otherwise plainly appears.³ The section is residual because it begins where the specific justifications stop. Self-defense and public duty address situations that legislatures foresaw and shaped with their own limits, while § 3.02 takes the emergencies that no such rule anticipated, such as the ambulance that passes a red light or the lost mountain climbers who take shelter in a house and use its provisions.⁴ The drafters adopted a general principle of necessity because a developed legal system needs a better way to handle such cases than applying the letter of prohibitions written without them in view.⁵

The section therefore sets four checkpoints, which the later sections take one at a time. The actor must have believed the conduct necessary; the harm avoided must be greater than the harm the offense targets; the legislature must not have displaced the general defense, whether through a specific exception under (1)(b) or a contrary purpose under (1)(c); and the actor must not have been reckless or negligent in creating the emergency or in appraising the need for action, a fault that under subsection (2) forfeits the defense for any offense that recklessness or negligence suffices to establish.⁶ The first two checkpoints allocate responsibility differently. The belief belongs to the actor, but the comparison of harms does not: subsection (1)(a) asks whether the harm avoided is in fact greater, whatever the defendant thought of the balance.⁷ An actor who sincerely overvalues a lesser harm therefore earns no justification. Before working through the checkpoints, the first section asks why a legal system would ever treat law-breaking as the right thing to do, since that answer explains the shape of each limit.