Model Penal Code Section 5.03 defines criminal conspiracy as an agreement to commit a crime made with the purpose of seeing that crime carried out. Unlike the common-law rule that asks whether a group reached a true meeting of the minds, MPC 5.03 criminal conspiracy focuses on each defendant’s own intent when they joined the plan. The section sets out the mental state, the two forms the agreement can take, when an overt act is needed, how the charge is graded, who counts as part of a single conspiracy, and how a person can get out.
The Agreement and the Purpose Requirement
Section 5.03(1) creates two paths to liability. In the first, a person agrees with one or more others that they will engage in conduct amounting to a crime, an attempt, or a solicitation. In the second, a person agrees to help plan or carry out someone else’s crime. Both paths require the same mental state: the defendant must act with the purpose of promoting or facilitating the offense.1Open Casebook. MPC 5.03 Criminal Conspiracy
Purpose is a demanding standard. Knowing about a crime, or suspecting one is coming, is not enough. A person who sells a tool they suspect might be used in a burglary has not conspired to commit burglary unless they sold it with the actual goal of helping the burglary happen. The prosecution must show the defendant genuinely wanted the criminal objective to succeed through the joint effort. That requirement separates conspiracy from the fuzzier territory of guilty knowledge.
The Unilateral Theory of Conspiracy
The MPC’s biggest departure from older conspiracy law is its unilateral approach. At common law and under the federal conspiracy statute, 18 U.S.C. ยง 371, conspiracy requires a genuine meeting of the minds between two or more guilty parties. If one party was faking, no conspiracy existed for anyone. The MPC abandons that rule and looks only at the defendant’s own state of mind.2Open Casebook. Model Penal Code 5.03 – Criminal Conspiracy
The practical consequence surfaces most often in sting operations. Under the bilateral approach, a defendant who agreed to a drug deal with an undercover officer could not be convicted of conspiracy, because the officer never intended to complete the crime. Under the MPC, that same defendant is guilty if they believed they were entering a real criminal agreement and acted with the purpose of seeing it through. The individual’s decision to join a criminal partnership is treated as the core danger, regardless of whether the other party was genuinely on board.
Section 5.04(1) reinforces this. Conspiracy liability is unaffected if the co-conspirator turns out to be legally irresponsible or immune from prosecution. If you believe you are conspiring with someone who can carry out the crime, your own culpability stands even if that person could never be convicted.
When an Overt Act Is Required
Section 5.03(5) splits conspiracies by the seriousness of the planned crime. For conspiracies targeting first- or second-degree felonies, the agreement itself is enough and no physical step is required. The MPC treats the bare act of planning a serious felony as dangerous enough on its own.1Open Casebook. MPC 5.03 Criminal Conspiracy
For every other crime, at least one conspirator must perform an overt act in furtherance of the plan. The act itself does not have to be illegal. Buying a map, renting a car, or opening a bank account can all qualify if done to advance the conspiracy’s objective. The requirement separates people who are moving toward a crime from people who are only talking.3OpenCasebook. Model Penal Code 5.03 Criminal Conspiracy
A boundary worth noting: the federal general conspiracy statute requires an overt act for all conspiracies it covers, with no exception for serious felonies.4Office of the Law Revision Counsel. 18 U.S. Code 371 – Conspiracy to Commit Offense or to Defraud United States States that have adopted the MPC framework often follow its tiered approach, but not all do; some require an overt act regardless of the target offense.
How Conspiracy Is Graded
MPC Section 5.05(1) sets the general rule: conspiracy is graded at the same level as the most serious crime the conspirators planned to commit. Conspiracy to commit a third-degree felony is itself a third-degree felony. Conspiracy to commit a misdemeanor is a misdemeanor.
There is one exception. A conspiracy to commit a first-degree felony, or a capital crime in jurisdictions that recognize the category, is graded one step down as a second-degree felony. The drafters treated this reduction as a concession to the fact that inchoate offenses have not yet produced the ultimate harm. The exception sits only at the very top of the severity scale; for every other grade, the conspiracy matches its target offense exactly.
Scope: One Conspiracy or Several
Sections 5.03(2) and 5.03(3) address two recurring problems: how far a single conspiracy extends across participants, and how multiple criminal objectives affect the count.
Multiple Criminal Objectives
When a group plans several different crimes, the MPC treats those plans as a single conspiracy so long as the crimes are part of the same agreement or an ongoing conspiratorial relationship.1Open Casebook. MPC 5.03 Criminal Conspiracy A crew that agrees to rob three banks over six months has committed one conspiracy, not three. The rule prevents prosecutors from stacking conspiracy charges for what is really a single criminal partnership with a running agenda.
Extended Liability Through Knowledge
Section 5.03(2) can connect people who have never met. If you know that the person you are conspiring with has also conspired with others to commit the same crime, you are legally conspiring with those other people too, even if you do not know who they are.2Open Casebook. Model Penal Code 5.03 – Criminal Conspiracy Knowledge of the broader scheme is the key. A mid-level drug distributor who knows the supplier is working with other distributors on the same operation becomes a conspirator with all of them. A distributor who genuinely believes they are the supplier’s only customer would not.
There are limits. Where separate groups share a common contact but have no awareness of each other and are pursuing independent objectives, the MPC treats those as separate conspiracies rather than one sprawling enterprise.
Getting Out: Abandonment and Renunciation
The MPC provides two mechanisms for leaving a conspiracy, and they offer very different levels of protection. Picking the wrong one can leave a defendant fully liable for everything the conspiracy does after they walk away.
Abandonment Under Section 5.03(7)
Section 5.03(7) defines when the conspiracy terminates for a particular individual. The conspiracy continues as a continuing course of conduct until either the target crimes are committed or the agreement is abandoned. For an individual who wants out, the conspiracy terminates as to them only if they take one of two concrete steps: advise their co-conspirators of their abandonment, or inform law enforcement about the conspiracy and their role in it.1Open Casebook. MPC 5.03 Criminal Conspiracy Simply going quiet or losing interest is not enough. Without an affirmative step, the conspiracy clock keeps running, which matters for the statute of limitations.
Abandonment is also presumed when no conspirator performs any overt act during the applicable limitations period. That backstop prevents stale conspiracies from being prosecuted indefinitely.
Renunciation Under Section 5.03(6)
Renunciation goes further. It is an affirmative defense that can result in a complete acquittal on the conspiracy charge. To claim it, the defendant must have thwarted the success of the conspiracy under circumstances showing a complete and voluntary change of heart.5Open Casebook. MPC Section 5.03 Abandonment stops the clock; renunciation erases the charge. The price is high. The defendant must actually prevent the conspiracy from succeeding, not just step aside and hope it falls apart.
Conspiracy and the Completed Crime Do Not Merge
Under the MPC, attempt merges with the completed offense. If you attempt a robbery and succeed, you are convicted of robbery, not both. Conspiracy works differently. A defendant can be convicted of both the conspiracy and the crime the conspiracy targeted.6Open Casebook. Criminal Law Casebook – Inchoate Offenses The rationale is that conspiracy represents a distinct social harm: the formation of a criminal group. Even after the group achieves its objective, the danger posed by the group’s existence is treated as a separate wrong from the harm of the completed crime.
A narrow exception sits in MPC Section 1.07(1), which bars conviction for multiple offenses when one offense consists only of a conspiracy or other form of preparation to commit the other. In practice, a defendant cannot be convicted of both conspiracy and a lesser included preparatory offense that was merely a step toward the conspiracy’s goal. For the primary target crime, dual convictions stand.
Liability for a Co-Conspirator’s Crimes
One of the most consequential questions in conspiracy law is whether joining a conspiracy automatically makes you liable for every crime your partners commit. Under the federal Pinkerton doctrine, the answer is yes, so long as those crimes were foreseeable and in furtherance of the conspiracy. The MPC rejects that approach. It channels co-conspirator liability through its accomplice liability framework in Section 2.06.7Open Casebook. Model Penal Code Section 2.06
Under Section 2.06, you are liable for another person’s crime only if you acted with the purpose of promoting or facilitating it, or if you aided, solicited, or agreed to aid in its commission. Mere membership in the same conspiracy is not enough. If a co-conspirator commits a murder during what was supposed to be a simple theft, the MPC will not hold you responsible for that murder unless the prosecution can show you specifically intended to facilitate it or helped bring it about. That is a meaningful protection compared to the Pinkerton rule, which critics have argued effectively reduces the mental-state requirement for serious crimes to something close to negligence.