Also known as: malum in se · mala in se crimes · inherently wrongful acts
Written by attorneys · grounded in primary & secondary sources — see below
A category of crimes or acts that are inherently immoral or wrong in themselves. Courts distinguish these from regulatory offenses that carry no inherent moral wrong.
Monica Morgan, captain of a small charter vessel, knowingly carried ten passengers when harbor rules limited the boat to six. In choppy seas the overloaded craft capsized and a passenger drowned. Because the capacity violation was treated as malum in se, the resulting death supported involuntary manslaughter under the misdemeanor-manslaughter rule without separate proof of foreseeability.
Miranda Morales, a hospital administrator, parked in a clearly marked ambulance-only zone to save time. An arriving ambulance carrying a heart-attack patient had to wait, and the patient died. Because the parking ordinance was merely malum prohibitum, the majority rule required proof that death was a foreseeable consequence of the violation before manslaughter liability attached.
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Mustafa Mahmoud, a long-time resident, never registered as required by a local ordinance after a prior conviction. Prosecutors charged him with the regulatory offense. The court treated the violation as malum prohibitum rather than malum in se, so the absence of any inherent moral wrong limited the scope of criminal liability.
Michael Miller accepted government surplus property believing it had been abandoned. Federal prosecutors charged him with conversion of public property. Because the underlying offense was classified as malum in se, the court required proof of criminal intent rather than treating the act as a strict-liability regulatory violation.
Malcolm McKinley, a prohibition-era enforcement agent, persuaded a reluctant citizen to obtain illegal liquor so that an arrest could be made. The citizen was later charged with the offense. The court viewed the underlying prohibition violation as malum prohibitum, requiring examination of whether the inducement created liability for an inherently wrongful act.
Mariam Mansour sold a substance later shown to contain opium. Prosecutors charged her under a federal narcotics statute that omitted any intent element. The Court treated the offense as malum prohibitum, allowing Congress to dispense with proof of knowledge because the conduct lacked the inherent moral wrong of traditional common-law crimes.
When the underlying misdemeanor is malum in se, most courts impose manslaughter liability for any resulting death without requiring separate proof that the death was foreseeable. When the misdemeanor is merely malum prohibitum, the majority rule requires that the death be a natural or foreseeable consequence of the unlawful conduct.
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Malum in se offenses are inherently immoral or wrong in themselves, such as murder, arson, or rape. Malum prohibitum offenses are wrong only because a statute or regulation prohibits them, such as many regulatory or safety violations.
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Yes. Crimes classified as malum in se traditionally require proof of mens rea because they involve conduct that is morally wrongful. Regulatory offenses classified as malum prohibitum may be enforced on a strict-liability basis without proof of intent.
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Courts generally treat safety regulations as malum prohibitum unless the conduct itself carries inherent moral wrongfulness. When the violation creates an obvious danger to human life, however, some decisions treat it as sufficiently wrongful to support manslaughter without additional foreseeability analysis.
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…of the statute is evidently upon achievement of some social betterment rather than the punishment of the crimes as in cases of mala in se .” Surely there can hardly be a difference as a matter of fairness, of hardship, or of justice, if one may invoke it, between the case of a person wholly innocent of wrongdoing, in the…