Wisconsin Statutes
Wis. Stat. § 939.47 (2026)
Necessity
✓ current as of July 2026
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939.47939.47 Necessity. Pressure of natural physical forces which causes the actor reasonably to believe that his or her act is the only means of preventing imminent public disaster, or imminent death or great bodily harm to the actor or another and which causes him or her so to act, is a defense to a prosecution for any crime based on that act, except that if the prosecution is for first-degree intentional homicide, the degree of the crime is reduced to 2nd-degree intentional homicide.
939.47 NoteJudicial Council Note, 1988: This section is amended by conforming references to the statute titles created by this bill. Since necessity mitigates first-degree intentional homicide to 2nd degree, it is obviously not a defense to prosecution for the latter crime. [Bill 191-S]
939.47 AnnotationThe defense of necessity was unavailable to a demonstrator who sought to stop a shipment of nuclear fuel on the grounds of safety. State v. Olsen, 99 Wis. 2d 572, 299 N.W.2d 632 (Ct. App. 1980).
939.47 AnnotationHeroin addiction is not a “natural physical force” as used in this section. An addict, caught injecting heroin in jail, who was not provided methadone as had been promised, was not entitled to assert necessity against a charge of possession of heroin because his addiction ultimately resulted from his conscious decision to start using illegal drugs. State v. Anthuber, 201 Wis. 2d 512, 549 N.W.2d 477 (Ct. App. 1996), 95-1365.
Notes of Decisions
Cited in 11
cases (5 in the last 5 years), 1980–2025 · leading case: State v. Hamdan, 2003 WI 113 (Wis. 2003).
State v. Hamdan, 2003 WI 113 (Wis. 2003). “§ 939.47 provides: Pressure of natural physical forces which causes the actor reasonably to believe that his or her act is the only means of preventing imminent public disaster, or imminent death or great bodily harm to the actor or another and which causes him or her so to act,…”
State v. Olsen, 299 N.W.2d 632 (Wis. Ct. App. 1980). “” Sec. 939.47, Stats. Examples of these forces are storms, fires, and privations.”
State v. Brown, 318 N.W.2d 370 (Wis. 1982). “" [7] Sec. 939.47, Stats. 1979-80, provides as follows: "939.”
State v. Dundon, 594 N.W.2d 780 (Wis. 1999). “" Wis. Stat. § 939.47 . In State v. Olsen, 99 Wis.”
State v. Horn, 377 N.W.2d 176 (Wis. Ct. App. 1985). “5 See Section 939.47, Stats. 6 We note that the holding in Roe, 410 U.”
State v. Chrystul D. Kizer, 2021 WI App 46 (Wis. Ct. App. 2021). “Like WIS. STAT. § 939.46(1), both §§ 939.”
State v. Anthuber, 549 N.W.2d 477 (Wis. Ct. App. 1996). “1980), the court identified the four elements which comprise the § 939.47, Stats., necessity defense: (1) the defendant must have acted under pressure from natural physical forces; (2) the defendant's act was necessary to prevent imminent public disaster, or death, or great…”
State v. Chrystul D. Kizer, 2022 WI 58 (Wis. 2022). “(citing Wis. Stat. § 939.47 (necessity is a complete defense "except that if the prosecution is for first-degree intentional homicide, the degree of the crime is reduced to 2nd- degree intentional homicide")).”
State v. Chrystul D. Kizer, 2022 WI 58 (Wis. 2022). “(citing Wis. Stat. § 939.47 (necessity is a complete defense "except that if the prosecution is for first-degree intentional homicide, the degree of the crime is reduced to 2nd- degree intentional homicide")).”
State v. Thomas K. Malmquist (Wis. Ct. App. 2021). “§ 939.47 (2017-18).1 There are four elements comprising this defense: (1) the defendant must have acted under pressure from natural physical forces; (2) the defendant’s act was necessary to prevent imminent public disaster, or death, or great bodily harm; (3) the defendant had…”
State v. Colin R. Dowling (Wis. Ct. App. 2025). “§ 939.47, which codifies the common law “necessity defense” doctrine, under which a person should not be punished for violating a law when the circumstances presented the defendant with a choice between breaking the law and enduring a greater harm.”
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