Wharton’s rule ([h]wor-t<<schwa>>n).Criminal law. The doctrine that 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 actual number of participants involved. • But if an additional person participates so as to enlarge the scope of the agreement, all the actors may be charged with conspiracy. The doctrine takes its name from the influential criminal-law author Francis Wharton (1820–1889). — Also termed Wharton rule; concert-of-action rule. [Cases: Conspiracy  28(1). C.J.S. Conspiracy §§ 209, 213–214.]

“Wharton’s Rule applies only to offenses that require concerted criminal activity, a plurality of criminal agents. In such cases, a closer relationship exists between the conspiracy and the substantive offense because both require collective criminal activity. The substantive offense therefore presents some of the same threats that the law of conspiracy normally is thought to guard against, and it cannot automatically be assumed that the Legislature intended the conspiracy and the substantive offense to remain as discrete crimes upon consummation of the latter. Thus, absent legislative intent to the contrary, the Rule supports a presumption that the two merge when the substantive offense is proved…. More important, as the Rule is essentially an aid to the determination of legislative intent, it must defer to a discernible legislative judgment.” Iannelli v. United States, 420 U.S. 770, 785–86, 95 S.Ct. 1284, 1293–94 (1975).
[Blacks Law 8th]