Conspiracy

Conspiracy is an inchoate crime that criminalizes the agreement itself to commit an unlawful act. At common law, the crime was complete upon the formation of the agreement, requiring no further action. The Model Penal Code and most modern statutes add the requirement of an overt act in furtherance of the conspiracy, though the overt act need not itself be criminal -- even a minor preparatory step suffices.

The agreement need not be formal or express; it can be inferred from the conduct and circumstances of the parties. The prosecution must prove that each conspirator intended to agree and intended that the substantive crime be committed. Under the Pinkerton doctrine, each conspirator is vicariously liable for all foreseeable crimes committed by co-conspirators in furtherance of the conspiracy, even if the defendant did not participate in or know about those specific crimes.

A critical distinction exists between the common law bilateral approach and the MPC unilateral approach. Under the bilateral approach, at least two genuinely agreeing minds are required; if one party is an undercover officer or feigning agreement, no conspiracy exists. Under the MPC's unilateral approach, a defendant can be guilty of conspiracy even if the other party is an undercover agent, because the focus is on the defendant's own culpability. Conspiracy does not merge with the completed substantive offense, meaning a defendant can be convicted of both conspiracy and the target crime. Withdrawal can terminate liability for future crimes of co-conspirators but does not eliminate liability for the conspiracy itself at common law.