Introductory Note: When two or more people agree to commit an act that is a crime, they can be convicted of “conspiracy” to do that act. This is true even if they don’t ever carry out the crime itself. (In fact, in most states, they can be convicted even if they don’t do anything more than make the agreement, and never carry out any acts in furtherance of the conspiracy). Conspiracy is an increasingly important prosecuto-rial tool whenever groups of people plan to commit crimes together.
A. Definition of “conspiracy”: The common-law crime of conspiracy is defined as an agreement between two or more persons to do either an unlawful act or a lawful act by unlawful means. At common law, the prosecution is required to show the following elements:
1. Agreement: An agreement between two or more persons;
2. Objective: To carry out an act which is either unlawful or which is lawful but to be accomplished by unlawful means;
3. Mens rea: A culpable intent on the part of the defendant. In the usual case of a conspiracy to commit an act that would be a crime, the intent must consist of at least the mental state required for the object crime. (For instance, for conspiracy to commit murder, each conspirator must have an intent that would suffice for the crime of murder.)
B. Purposes of conspiracy law: There are two principal purposes that are served by defining and proscribing the crime of conspiracy:
1. Inchoate crime: First, since a conspiracy may be (and frequently is) found where no substantive crime is ever committed, society is able to stop conduct before the harmful effects of substantive criminality occur. Thus conspiracy is an “inchoate” crime, and serves the same functions as the law of attempts (supra, p. 153).
2. Group activity: Secondly, it is often felt that group activity of a criminal nature is more dangerous than criminal conduct engaged in by an individual working alone. Under conventional theory, persons working in combination will give each other courage, dissuade each other from abandoning the criminal plan, and render each other mutual assistance that makes the ultimate success of the crime more likely. Thus the law of conspiracy serves a function of policing group activity.
a. Contrary view: Others have pointed out, however, that there is no empirical evidence that group criminality is more likely to succeed than solo activity, and that there are theoretical reasons why this may not be so. For instance, the risk of a leak to law enforcement authorities, and the risk that one of the participants may be an undercover agent, are obviously potent anti-success factors that are not present when an individual works alone. See Commentary to M.P.C. § 5.03, fn. 17.