Criminal Conspiracy

Criminal conspiracy is an inchoate offense consisting of an agreement between two or more persons to commit a crime, typically accompanied by an overt act in furtherance of the conspiracy. The offense is distinct from the target crime itself — a defendant can be convicted of both conspiracy and the completed offense without violating double jeopardy principles, because conspiracy punishes the agreement while the substantive offense punishes the criminal act.

Under the traditional bilateral approach, a conspiracy requires at least two guilty minds. If one of the two alleged co-conspirators is acquitted, the remaining defendant cannot be convicted of conspiracy (the Gebardi rule). The Model Penal Code adopts a unilateral approach under which a defendant can be convicted of conspiracy based on their own agreement, regardless of whether the other party is convicted, was feigning agreement, or was an undercover officer. Most modern jurisdictions follow the MPC's unilateral approach.

The overt act requirement varies by jurisdiction. At common law and under the MPC, any act — even a trivial preparatory step — suffices to show that the conspiracy has moved beyond mere talk. Some federal conspiracy statutes (such as 18 U.S.C. Section 371) require an overt act, while others (such as drug conspiracy under 21 U.S.C. Section 846) do not. The overt act requirement serves an evidentiary function, corroborating the existence of the agreement.

The Pinkerton doctrine extends conspiracy liability further: each conspirator is liable for the foreseeable substantive crimes committed by co-conspirators in furtherance of the conspiracy. This means that a defendant who joined a conspiracy to rob a bank can be held liable for a murder committed by a co-conspirator during the robbery if the murder was a reasonably foreseeable consequence. The Pinkerton rule dramatically expands criminal liability and is one of the most important doctrines in conspiracy law.