Wharton's Rule

Wharton's Rule

The plurality requirement developed so far asks whether an agreement supplies two guilty parties, counted as legal persons. Wharton's rule adds a further limit on that count, and the limit comes from the crime the parties agreed to commit rather than from who the parties are. Under the rule, an agreement by two or more persons to commit a particular crime cannot be prosecuted as a conspiracy if the crime could not be committed except by the number of participants actually involved.¹ Bribery, which needs a giver and a taker, and adultery, which needs two people, are the standard illustrations.² The rule narrows the plurality requirement for a small class of offenses and adds no element the prosecution must prove in an ordinary conspiracy, so it matters only when the substantive crime is itself built around joint participation.

The reason for the rule lies in why conspiracy is punished separately at all. An agreement makes the intent to commit a crime less equivocal and makes the planned crime more likely to be carried out, which is why the law reaches back to the planning stage.³ When the substantive crime can be committed only by two or more people, however, the group is already part of the definition of the crime. The agreement among the necessary participants is then the ordinary preparation for the offense, and a conspiracy charge adds no danger from numbers beyond what the offense already punishes.⁴ In Iannelli v. United States the Supreme Court put the point in terms of legislative intent: an offense that requires concerted criminal activity already presents some of the threats conspiracy law guards against, so it cannot be assumed that the legislature meant the conspiracy and the completed offense to remain separate crimes.⁵

Because the rule is tied to the number of participants the offense requires, its main exception follows directly. If an additional person participates so as to enlarge the scope of the agreement, all the actors may be charged with conspiracy.⁶ The adultery illustration shows the exception at work: the two people who commit adultery cannot normally be prosecuted for both that offense and a conspiracy to commit it, but a matchmaker who conspires with them to encourage the offense brings the group beyond the number the offense requires.⁷ The same reasoning applies to two bribers and a bribee, where the prevailing but not universal rule permits a conspiracy conviction.⁸ The explanation offered is that a third participant enhances the danger the crime presents, so the legislature is not taken to have meant to forbid punishment for a combination larger than the offense itself demands.⁹

Authorities differ on how much work the rule does once it applies. Stated as a limit on conspiracy itself, it prevents the conspiracy charge from being prosecuted at all when the offense requires only the participants involved.¹⁰ Stated as in Iannelli, it is a judicial presumption about legislative intent: absent a contrary legislative purpose, the conspiracy is presumed to merge into the completed offense, and the presumption gives way to any discernible legislative judgment.¹¹ The Court there rejected the traditional application of the rule as a substantive limitation on conspiracy, and it found a legislative intent contrary to the rule under the federal gambling statute, 18 U.S.C. § 1955.¹² The difference has practical consequences. Under the bar formulation, the question is whether a conspiracy charge may be brought at all, while under the merger formulation, the question is whether the defendant may be convicted of both the conspiracy and the completed offense, and legislative intent can answer yes. Because the authorities do not settle on one formulation, an answer should state the one the jurisdiction in the stem applies and, where the stem is silent, describe both.

The rule is triggered by an offense that penalizes the whole group it requires. When a statute penalizes only one of the necessary parties, the offense does not itself punish the group, and the other party's agreement is not covered by the substantive crime, so the rule has no reason to apply.

The duel and the narcotics sale differ in one respect, which is who the offense punishes. A dueling statute reaches both combatants, so the offense definition already covers the whole group, while the narcotics statute reaches the seller alone. A further limit keeps the rule narrow: it does not apply merely because two people happened to commit an offense together. Students lose this issue when they apply the rule to a crime that two people can choose to commit together but one person could commit alone, such as a fraud, because only an offense that cannot be committed except by the participants involved triggers the rule.¹³ The Model Penal Code rejects the rule on the ground that any agreement to commit a crime should be punished as a conspiracy, and a later section takes up that contrast.¹⁴