Actus Reus
Rule
Criminal liability requires a voluntary act (or a qualifying omission). An act is voluntary if it is a willed bodily movement. Involuntary acts (reflexes, convulsions, somnambulism, automatism) do not satisfy the actus reus requirement.
Elements
- Voluntary act — a willed bodily movement; presupposes conscious control over bodily movement
- Omission — criminal liability for failure to act is permitted only where the defendant had a legal duty to act:
- Special relationship (parent-child, spouse, in loco parentis)
- Contractual undertaking to provide care (Pestinikas)
- Voluntary undertaking of rescue followed by abandonment
- Creation of the hazard
- Duty imposed by statute
- Undertaking that induces reliance
- Voluntariness of omission: where the individual cannot reasonably perform the required act, the duty is lifted
MPC vs Common Law
- MPC § 2.01: liability requires that conduct include a voluntary act; MPC also provides no omission liability unless a duty is imposed by law
- Both MPC and CL agree: no general duty to rescue (unlike some civil law jurisdictions)
- No liability for omission unless there is a preexisting duty to act; mere presence and failure to assist does not create liability unless actor “encouraged” the crime (making them an accomplice)
Exceptions / Defenses
- Automatism: may be treated as (1) a denial of voluntariness of actus reus, or (2) a species of insanity (affirmative defense); classification matters because insanity is an affirmative defense in many jurisdictions
- Strict liability offenses: may eliminate voluntariness as a formal element (State v. Deer)
- Duty limitations: physicians have no legal duty to continue futile treatment; good Samaritans generally incur no criminal duty
Policy
- Punishing involuntary acts would be arbitrary and fail to deter (one cannot conform behavior one cannot control)
- Requiring a legal duty for omission liability prevents expansive criminal liability for mere failure to rescue and respects individual liberty
- Omission liability where a legal duty exists reflects the reasonable expectation that those who voluntarily assume care obligations will fulfill them
Key Cases
- State v. Utter — conditioned reflex from combat training rejected as either automatism affirmative defense or negation of actus reus; no evidence sufficient to support either theory
- Commonwealth v. Pestinikas — contractual duty to provide care to elderly man satisfied legal duty requirement for omission liability; voluntary assent to contract creates the duty
- State v. Davis — court expanded special relationship doctrine to cover a non-biological male figure with children relying on his protection