The Voluntary Act Requirement

The Voluntary Act Requirement

The baseline rule fits in a single sentence of the Model Penal Code: "A person is not guilty of an offense unless his liability is based on conduct which includes a voluntary act or the omission to perform an act of which he is physically capable."¹ The wording repays slow reading. Liability must rest on what the person did or failed to do. The conduct also need only include a voluntary act, which means not every movement in a course of conduct has to be willed. One voluntary act anywhere in the sequence supplies the foundation, a point that matters later when harm arrives at a moment the person no longer controls.²

Because the rule governs every offense, every crime has a conduct element. Usually that element is an act, and the act element is called the actus reus, a Latin phrase for the guilty act that names the physical side of an offense as distinct from its mental side.³ (An omission can stand in for an act only on the conditions that later sections set out.) The prosecution therefore has to prove beyond a reasonable doubt that the defendant engaged in at least one voluntary act.⁴ That burden does not disappear when the offense requires no mental state, because strict liability offenses still require a voluntary act.⁵ Dropping a mental-state element removes the question of what the defendant was thinking. It leaves in place the earlier question whether the defendant did anything that was the defendant's own.

The requirement has more than one justification, and each points to a different feature of the rule. Deterrence explains why involuntary movements are excluded. Punishment works by attaching a cost to a choice so that people choose differently, and a spasm offers no choice for the threat to act upon, so punishing it causes suffering and prevents nothing.⁶ Desert reaches the same exclusion from the other direction, since a person who did not choose a harmful movement has done nothing that deserves blame.⁷ Where an involuntary condition poses a continuing danger, such as a seizure disorder, other systems of care and control, including involuntary hospitalization, can respond without any conviction.⁸ The drafters of the Model Penal Code added a point about social security: personal security would erode in a society where movement or inactivity beyond a person's control could bring formal condemnation.⁹ The separate demand for conduct has its own reasons, which appear below with thoughts and status.

The contrast the introduction drew with two anonymous drivers appears in the standard teaching pair, which holds everything constant except the movement itself. John sees his rival at a crowded sidewalk café, floors the accelerator, and steers into the diners, killing several, his target among them.¹⁰ Jane, on a similar street, is seized by a sudden spasm that extends her foot onto the pedal and jerks her hands onto the wheel, and her car enters a crowded café and kills several customers.¹¹ In most jurisdictions John is punished and Jane is not, because John's pressing of the pedal and turning of the wheel were voluntary acts, while Jane's identical movements were the products of involuntary spasms.¹² The deaths, the car, and the café are the same on both sides, so the fact that moves the answer is whether the movement was the driver's choice. Jane's freedom from liability holds only for the spasm itself. A driver who knew of a tendency to such spasms and drove anyway presents a different question, which the section on earlier voluntary conduct takes up.

Applying the rule requires knowing what an act is and what makes one voluntary. The Code answers the first question broadly: an act is a bodily movement, whether voluntary or involuntary.¹³ Because that definition sweeps in spasms and deliberate steps alike, the work of separating them falls to the word voluntary, which the Code does not define; its commentary treats a voluntary act as behavior within the actor's control.¹⁴ The omission makes sense because the affirmative definitions break down. If a voluntary act were a willed bodily movement, one would have to ask whether a person wills each muscle flexion in lifting a book or each step in walking down a hall, and most of what people do each day is automatic rather than the product of deliberate decision.¹⁵ The criminal law therefore sidesteps the definition. A voluntary act is simply an act that is not involuntary, and the Code gives that negative its content by listing the kinds of movement that fall outside the category, which the next section examines.¹⁶

Because the test turns on control, a movement does not become involuntary merely because it was habitual or inattentive. A parent who has been told the child needs no ride, but who drives to the child-care center anyway out of long habit or while daydreaming, performs a voluntary act, since the parent could have behaved differently.¹⁷ Jane's spasm differs on exactly that point: at the moment of the spasm she could not have done otherwise. The rule has to work this way because a great deal of criminal conduct, careless driving being the obvious example, is inattentive. A requirement of conscious deliberation would let nearly every inattentive offender escape the act element.

What the requirement excludes follows from the same demand for conduct, and the first exclusion is thought. A wish, or even a settled intention, to commit a crime is not an act, and the law does not punish an unexecuted intent standing alone.¹⁸ Two practical reasons support the line. No one can reliably tell what another person is thinking, much less whether the thinker will act on it, and if fantasies about crime were punishable, most people would be exposed to liability.¹⁹ A legislature may still reach an intention that is accompanied by some act, so the line falls at conduct.²⁰

In the diary scenario, attempt does not fill the gap, because the Code's attempt provision itself requires an act or omission amounting to a substantial step toward the offense.²¹ The spoken instruction counts as conduct because speaking is usually treated as an act, in a way that a private resolve is not.²²

Status presents the same problem from another angle. A condition such as being a vagrant is a state a person is in, not something the person does, so a statute that punishes the condition alone dispenses with the act requirement. Courts have not always struck such statutes down, but there is a growing body of authority holding vagrancy-type laws invalid.²³ The Supreme Court has also cast serious doubt on whether a state may ever punish mere status without proof of some irregular behavior, and a legislature cannot make it a crime to hold a reputation as a habitual criminal.²⁴ The practical consequence is that a legislature concerned about a social problem must define the offense around behavior.

The Alabama statute in Martin v. State illustrates that drafting choice. It reached a person who, while drunk, appeared in a public place and manifested the condition by boisterous or indecent conduct or by loud and profane discourse.²⁵ Appearing drunk in public and making a scene is behavior that a legislature can define as an offense, whereas a statute punishing the condition of being an alcoholic would face the status objection. Even so, the Alabama Court of Appeals reversed Martin's conviction. Police officers had arrested him at home and carried him onto the highway, and the court held that a charge of public drunkenness cannot be established by proof that the accused was involuntarily and forcibly carried to the public place by the arresting officer.²⁶ The case shows the act requirement operating on a single element of an offense, and it returns in the discussion of movements that are not the person's own.

One qualification keeps the requirement from being read too literally. The rule concerns control and choice, and it does not demand an actual muscle movement in every case. In narrow settings, such as a crime boss who authorizes a killing by staying silent when an underling asks whether to proceed, or a party whose agreement in a conspiracy is expressed without movement, the law treats an act as having occurred because the circumstances show the actor's intention and willingness to see the deed done.²⁷ Those circumstances serve the purposes of the act requirement as effectively as a physical act would.²⁸