Actus reus refers to the act or omission that comprise the physical elements of a crime as required by statute. Actus reus includes only a voluntary affirmative act, or an omission (failure to act), causing a criminally proscribed result.
For example, if a thief shoves a gun into the side of a victim and says: “Your money or your life” - the shoving of the gun is the actus reus.
An involuntary act does not satisfy the actus reus requirement.
The actus reus includes only voluntary bodily movements, particularly one which society has an interest in preventing. This was confirmed by the Supreme Court in Powell v. Texas, 392 U.S. 514 (1968). Thus, if a defendant acted on reflex, then the defendant's conduct does not satisfy the actus reus requirement. Contrast this with mens rea, which refers to the criminal intent element of a crime.
Alternately, the actus reus requirement can also be satisfied by an omission. This is true only when the individual had a duty to act, and failed to act.
Generally, for the purposes of criminal liability, an individual may be under a duty to act if:
[Last updated in June of 2022 by the Wex Definitions Team]