§ 14.01 GENERAL PRINCIPLES

• Jurisdiction: United States

§ 14.01. General Principles¹

[A] "Causation": An Element of Criminal Responsibility

D points a gun at V, intending to kill V. A few seconds before D pulls the trigger, X, independently² of D, shoots and instantly kills V. The bullet in D's gun strikes the already dead V. Is D guilty of murder?

The answer, of course, is "no." A crime is composed of an actus reus and, almost always, a mens rea. As described elsewhere,³ the "actus reus" of an offense consists of a voluntary act (or an omission, when there is a duty to act) that results in the social harm prohibited by the offense. The "mens rea" is the culpable state of mind.

In the hypothetical, D's conduct included a voluntary act—pulling the trigger of the gun. The social harm of murder — the killing of a human being by another human being — occurred. Moreover, D intended to kill V, a sufficient mens rea for murder. It would appear, then, that everything is in place for D's murder conviction. Common sense, however, tells us that D is only guilty of attempted murder, rather than murder.

Common sense is confirmed by another prerequisite to criminal responsibility: causation. Analytically, "causation" is an ingredient of a crime's actus reus.⁴ A careful look at the definition of "actus reus," provided above, indicates that there must be a link between the voluntary act (or omission) and social harm. That link is "causation"; the defendant's voluntary act (or omission) must "result in"—cause—the social harm. And, as explained in this chapter, "causation" consists of two constituent parts, "actual cause" (or "cause in fact"), and "proximate cause" (or "legal cause").⁵

"Causation" is an implicit component of all crimes.⁶ It must be proved by the prosecution, as with all other elements of an offense, beyond a reasonable doubt.⁷ As a practical matter, however, "causation" only is an issue in the prosecution of "result" crimes, i.e., when the social harm of an offense is an unwanted result (e.g., the death of another human being).⁸ Indeed, causation problems seldom arise outside the context of homicide prosecutions.

Returning to the initial hypothetical, D will not be guilty of murder for the simple reason that X —not D—caused V's death. D is not legally responsible for a result that he did not cause. He may be held responsible, however, for the harm he did cause, for example, the social harm that results from the commission of an attempted murder.

[B] "Causation": Its Role in Criminal Law Theory

Causation analysis is so common a part of everyday thought processes that it is easy to ignore or downplay its importance in the criminal law. In fact, however, "causation" is a concept deeply imbedded "in human thought and expressed even among the most [ancient] people in their effort to understand 'the way of things.' "⁹

The role of causality in the criminal law...