MPC § 2.01: Requirement of Voluntary Act
What does Requirement of Voluntary Act (Model Penal Code) provide?
Section 2.01 establishes the foundational requirement that criminal liability must be based on conduct that includes a voluntary act or the omission to perform an act of which the defendant is physically capable. This is the MPC's codification of the actus reus requirement. A person is not guilty of an offense unless their liability is based on conduct that includes a voluntary act or the omission to perform a duty they are physically capable of performing.
Source: Model Penal Code § 2.01
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Summary
Section 2.01 establishes the foundational requirement that criminal liability must be based on conduct that includes a voluntary act or the omission to perform an act of which the defendant is physically capable. This is the MPC's codification of the actus reus requirement. A person is not guilty of an offense unless their liability is based on conduct that includes a voluntary act or the omission to perform a duty they are physically capable of performing.
The section specifically enumerates what does not constitute a voluntary act: a reflex or convulsion, a bodily movement during unconsciousness or sleep, conduct during hypnosis or resulting from hypnotic suggestion, and any bodily movement that is not otherwise a product of the effort or determination of the actor, either conscious or habitual. Importantly, liability can rest on conduct that includes a voluntary act — the entire sequence of behavior need not be voluntary so long as some voluntary act contributed to the criminal result.
Section 2.01 also addresses liability for omissions, stating that liability based on an omission is properly established only if the omission is expressly made sufficient by the law defining the offense, or if a duty to perform the omitted act is otherwise imposed by law. Additionally, the section clarifies that possession is an act for purposes of criminal liability if the possessor knowingly procured or received the thing possessed, or was aware of their control over it for a sufficient period to have been able to terminate possession.
Key Provisions
4 essential provisions of § 2.01
A person is not guilty of an offense unless liability is based on conduct that includes a voluntary act or an omission to perform an act of which they are physically capable
Not voluntary: reflex or convulsion; bodily movement during unconsciousness or sleep; conduct during hypnosis or resulting from hypnotic suggestion; bodily movement not a product of effort or determination of the actor
Liability for omission exists only if the omission is made sufficient by the law defining the offense or a duty to act is otherwise imposed by law
Possession is an act if the possessor knowingly procured or received the thing possessed or was aware of their control for a sufficient period to terminate possession
MPC vs. Common Law
How the MPC approach to requirement of voluntary act differs from common law
The common law voluntary act requirement developed through cases like Martin v. State (where a defendant was convicted of public drunkenness after police carried him onto a public highway) and People v. Newton (where an unconscious reflex action after being shot was held involuntary). The MPC codifies and clarifies these principles. The common law was less precise about what constituted involuntary conduct — the MPC provides a specific enumerated list. The common law also had a more developed but less consistent doctrine of omission liability, with duties arising from status relationships (parent-child), contract, voluntary assumption of care, creation of peril, and statutory duty. The MPC simplifies this by requiring either a statutory basis or a duty otherwise imposed by law, though courts interpreting the MPC still generally recognize common law duty categories.
Exam Relevance
How § 2.01 appears on criminal law exams
Voluntary act questions are staples of criminal law exams. Classic patterns include: a defendant who commits an act while sleepwalking, having a seizure, or under hypnosis; a fact pattern where the defendant's voluntary act is separated in time from the harmful result (e.g., choosing to drive despite knowing about a seizure condition — the voluntary act is getting behind the wheel); omission liability where the question is whether a legal duty exists; and possession cases testing whether the defendant had sufficient awareness and time to terminate possession. Students should be careful to note that only one voluntary act in the chain of conduct is needed — the defendant need not have been acting voluntarily at the precise moment of harm.
Related Sections
Sections frequently studied alongside § 2.01
More from Article 2 — General Principles of Liability
Other sections in Article 2