Also known as: voluntary act · voluntariness requirement · actus reus voluntariness
Written by attorneys · grounded in primary & secondary sources — see below
A principle of criminal law providing that no person may be convicted of an offense unless the prohibited conduct includes a voluntary act or the omission to perform an act of which the person is physically capable. A volitional act is a bodily movement willed by the actor. Certain movements such as reflexes, convulsions, or actions during unconsciousness or sleep are excluded from the category of voluntary acts.
A worker with a known seizure disorder suddenly convulses while adjusting monitoring knobs at a waste facility. The convulsion disables the alarm and allows untreated sludge to continue flowing. Because the movement is a reflex rather than a willed act, it supplies no voluntary conduct on which to base liability for the resulting environmental release.
A lender holding a promissory note from a borrower intentionally cancels the instrument by striking through the borrower's signature and writing the word 'paid' across the face. The lender then sues for the underlying debt. The cancellation is an intentional voluntary act that discharges the borrower's obligation on the note.
Select any source to read its text and confirm it supports the definition.
A doctor writes a prescription for lethal medication at the request of a terminally ill patient who wishes to end life. The patient later ingests the medication. The doctor's act of writing the prescription is a voluntary affirmative act that supplies the conduct element for any potential criminal charge arising from the patient's death.
A defendant stands in open court and verbally admits guilt to robbery charges after consulting with counsel. The plea is later challenged as involuntary. The defendant's spoken admission and signature on the plea form constitute voluntary acts that satisfy the conduct element of the offense for purposes of conviction.
A federal agent physically enters and searches a residence located in another country without a warrant. The entry and subsequent seizure of documents are voluntary bodily movements that constitute the conduct element of any Fourth Amendment claim arising from the search.
A defendant raises a gun, aims it at a victim, and pulls the trigger during an argument. The resulting shot kills the victim. The defendant's deliberate raising and firing of the weapon are voluntary acts that satisfy the conduct requirement for homicide liability.
Liability requires conduct that includes a voluntary act or a capable omission. A voluntary act is a willed bodily movement. Reflexes, convulsions, and movements during unconsciousness or sleep are excluded.
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Possession qualifies as a voluntary act only when the person knowingly receives the item or remains aware of control over it for a period sufficient to permit termination of possession.
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A bodily movement that occurs while a person is asleep or unconscious is not a voluntary act. Criminal liability cannot rest on such movements even if the person created the conditions leading to unconsciousness.
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An omission satisfies the requirement only when the person is physically capable of performing the omitted act and the law imposes a duty to act.
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…to make known that which might subject him to punishment, it was not intended to shield him from the consequences of his own voluntary act.' 161 U.S., at 595-596." Id. , at 427-428. In Murphy v. Waterfront Commission , 378 U.S. 52, decided today, we held that a state immunity statute which provided that no testimony given…