Mens Rea: Required mental states

Mens rea--Latin for 'guilty mind'--is the traditional common law term for the state of mind that must accompany conduct in order for one to be guilty of a crime. The materials in this section introduce you to the concept of mens rea. Like actus reus, mens rea weaves together ideas about the offender's blameworthiness, the seriousness of the crime, and the punishment that should be imposed. Mental state is critical to determining culpability. It is universal intuition that there is a moral difference between doing something knowingly v. unknowingly, intentionally v. unintentionally, or intentionally-but-carefully v. intentionally-but-negligently or recklessly. Justice Oliver Wendell Holmes expressed this notion in a now-famous aphorism: “Even a dog knows the difference between being kicked and being stumbled over.”

Courts and legislatures in the U.S. (and those in the United Kingdom and other common law countries) continue to use a wide variety of traditional terms developed in the common law to describe required mens rea or mental states for crimes, such as: scienter, intent, purpose, knowledge, malice/maliciously, corrupt/corruptly, and more. But two terms are especially widely used and important--"general intent" and "specific intent." "At common law, crimes generally were classified as requiring either 'general intent' or 'specific intent.'" United States v. Bailey, 444 U.S. 394, 403 (1980). Don't expect clear, consistent definitions of these terms that are easy to understand and apply. "This venerable distinction ... has been the source of a good deal of confusion." Id. This confusion arises in part because courts have been unable to consistently define general and specific intent, which has led some courts discourage trial judges, when instructing juries on mens rea requirements, to “eschew use of difficult legal concepts like 'specific intent' and 'general intent.'" Liparota v. United States, 471 U.S. 419, 433 n.16 (1985). In part because “the mental element in criminal law encompasses more than the two possibilities of 'specific' and 'general' intent." Liparota, at 423 n.5. And in part difficulties arise because legislatures do not employ these terms consistently in criminal codes, or draft criminal statutes carefully with these terms in mind.

Additionally, as we will later see, there are also strict liability offenses: crimes for which the defendant's state of mind is irrelevant. These typically involve acts/harms determined to be particularly injurious to public health and must be deterred/punished regardless of intent. To be convicted under a strict liability statute, the defendant must only have committed a voluntary act (actus reus) that caused the harmful result (causation) the statute was designed to prevent. Some examples of strict liability offenses are traffic violations, statutory rape, and felony murder. (Note that for all these offenses, the actor is knowingly doing something--driving, having sex, committing a non-homicide felony. But no knowledge, intent, or unreasonableness is required as to the resulting strict liability crime.)

The following cases provide an introduction to some of the challenges of defining precisely what those terms mean, or require, in particular criminal statutes. As you read these cases, consider what reasoning courts use to justify their decisions and what these reasons reveal about the evolving concept of blameworthiness. Always pay close attention to how the "guilty" state of mind is framed by the relevant statute(s) and the relationships between various mens rea and the severity of punishment. 

We then turn to a modern reform effort to replace these common law terms with different, perhaps-more-precise culpability terms--those proposed by the American Law Institute's Model Penal Code, which have been adopted in a fair number (roughly half) of state criminal codes and somewhat influential even in jurisdictions that have not formally enacted them. As we will see, the MPC categorizes culpable mental states into four tiers of culpability: purposely (acting with a conscious objective to produce the offense specified in the statute); knowingly (acting while being practically certain of the offending result); recklessly (acting with a conscious disregard for the risk of causing the offending result); and negligently (causing the offending result when the actor should have been aware of the risk). See MPC s 2.02(3).

While many statutes will seem loosely based on the four-tiered MPC framework, you should not assume they are identical. Courts often cite the MPC as persuasive (that is, influential but not formally binding) authority, but it is important to remember that the enacted legislation, and not the MPC, is what controls within any jurisdiction. In other words, even if a statute uses the mens rea term "intentional" in a manner akin to the MPC's definition of "purposeful," one may not necessarily substitute one term for another. As you work through these cases, train yourself to focus squarely on the actual language of a given statute and how a lawyer advocating for either side might interpret it.