---
title: "Necessity Defense"
type: Legal Rule
source: https://casebriefly.com/legal-rules/necessity-defense
---

# Necessity Defense

The necessity defense (choice of evils) justifies criminal conduct when the defendant reasonably believed their actions were necessary to avoid a greater harm than the harm caused by the criminal act.

## Definition

The necessity defense, also known as the choice of evils defense, justifies otherwise criminal conduct when the defendant was faced with a choice between two harms and reasonably chose the lesser evil. The defense is rooted in the utilitarian principle that the law should not punish conduct that produces a net social benefit by preventing greater harm. It is a justification defense, meaning that if successful, the defendant's conduct is deemed lawful.

For the defense to apply, the defendant must face a clear and imminent threat of harm with no reasonable legal alternative available. The harm the defendant seeks to avoid must be greater than the harm caused by the criminal act. The defendant must not have created the emergency or been at fault for the circumstances giving rise to the choice. Courts apply an objective standard, asking whether a reasonable person in the defendant's situation would have believed the criminal act was necessary to prevent the greater harm.

The necessity defense is narrow in scope and rarely successful. Courts are generally reluctant to allow defendants to substitute their judgment for the legislature's determination of what is criminal. The defense is not available for homicide in most jurisdictions, reflecting the principle that one may not intentionally take an innocent life to save others. It is also generally unavailable as a defense to political protests or civil disobedience, where the defendant deliberately violates the law to make a social statement. The Model Penal Code codifies the defense in Section 3.02, requiring that the harm sought to be avoided is greater than that sought to be prevented by the law defining the offense charged.

## Elements

- The defendant faced a clear and imminent threat of harm
- No reasonable legal alternative was available to avoid the threat
- The harm avoided was greater than the harm caused by the criminal act
- The defendant did not create the emergency or was not at fault for the situation
- The defendant reasonably believed their conduct was necessary to avoid the greater harm

## Key Case

Regina v. Dudley and Stephens, 14 Q.B.D. 273 (1884)

## Landmark Cases

| Name | Citation | Significance |
| --- | --- | --- |
| Regina v. Dudley and Stephens | 14 Q.B.D. 273 (1884) | Rejected the necessity defense for killing and eating a shipwreck companion, establishing that necessity does not justify intentional homicide |
| United States v. Bailey | 444 U.S. 394 (1980) | Held that prison escape defendants must show a bona fide effort to surrender immediately after reaching safety to invoke necessity |
| Nelson v. State | 597 P.2d 977 (Alaska 1979) | Recognized the necessity defense and outlined its elements, applying it in the context of property destruction to prevent greater harm |

## Exam Tips

- Always compare the harm avoided to the harm caused; the defendant's crime must be the lesser evil
- Check for a reasonable legal alternative; if one existed, the necessity defense fails
- Remember that necessity generally does not justify intentional homicide
- Distinguish necessity from duress: necessity involves natural forces or circumstances, while duress involves human threats

## Common Mistakes

- Confusing necessity with duress; necessity arises from natural forces or circumstances, while duress involves threats from another person
- Assuming economic necessity qualifies; financial hardship generally does not support a necessity defense for theft
- Forgetting that the defendant must not have caused the emergency; self-created necessity is typically not a defense

## Mnemonic Or Memory Aid

"Lesser of two evils" -- necessity requires choosing the lesser harm when there is no lawful way out

## Related Rules

- duress-defense
- self-defense
- actus-reus

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Source: [Necessity Defense — CaseBriefly](https://casebriefly.com/legal-rules/necessity-defense)