To access this feature, please Log In or Register for your Casebriefs Account.

Add to Library




Actus Reus


Actus Reus


The criminal law needs a practical and consistent method to describe the behavior for which its special power of arrest, conviction, and punishment may be used. Simply put, it needs a basic architecture to define crime. Although they may differ on their reasons, most utilitarians and retributivists agree on the basic elements of a crime.

Voluntary Act. Subject to some exceptions we will discuss shortly, the criminal law only punishes voluntary action; it does not punish inaction or mere thinking. The “voluntary act” element of a crime is usually called the actus reus.

Many utilitarians would argue that involuntary behavior should not be criminalized because it cannot be deterred. Retributivists would claim that an individual who did not choose to do a wrongful act does not deserve punishment. Moreover, other systems of care and control, such as involuntary hospitalization, are used for individuals perceived to pose an ongoing threat of harm by involuntary acts.

There are good reasons why the criminal law does not punish thoughts without action. First, it is extremely difficult to tell what a person is thinking, let alone whether he will act on those thoughts by committing a crime. Second, without this limitation, perhaps most of us would be subject to the reach of the criminal law because we fantasize about committing a crime at one time or another!

Omission and Legal Duty. The criminal law generally punishes an individual only for the affirmative harm he himself inflicts; it does not punish for failing to prevent harm caused by others or by natural forces. (Note, however, that speaking words is usually considered an act rather than “mere thoughts” in the criminal law.)

In limited cases, however, the failure to act—usually called an omission—may be a crime if the defendant had a legal duty to act. Of course, the defendant must have been capable of doing the legally required act because “the law cannot hope … to stimulate action that cannot physically be performed.” [1]

Sometimes a criminal statute explicitly requires an individual to act. A common example is the federal statute requiring most people to file an income tax return. Failure to file the return is considered a voluntary act rather than an omission because the statute specifically defines the failure to file as the prohibited “voluntary act.” [2]

[1] Model Penal Code and Commentaries 214-215 (1985).
[2] In the real world we think of a failure to file as an omission because the taxpayer has not done what he was supposed to do.

Create New Group

Casebriefs is concerned with your security, please complete the following