PastPaperHero | Inchoate crimes; parties

Learning Outcomes

This article explains conspiracy within the law of inchoate crimes, including:

The core elements of conspiracy—agreement, intent to agree, intent to achieve the unlawful objective, and (where required) an overt act—and how to spot them in MBE fact patterns
The distinctions between common law bilateral and modern or MPC unilateral approaches, and how undercover officers, acquittals, and legally incapable partners affect the existence of a conspiracy
How conspiracy interacts with attempt and solicitation, including non‑merger of conspiracy with the target offense and the circumstances in which solicitation effectively merges into conspiracy
The scope of co-conspirator liability under the Pinkerton rule, and how chain versus spoke-hub structures, withdrawal, and termination of the agreement expand or limit responsibility for substantive crimes
Key defenses and limiting doctrines on the exam—legal versus factual impossibility, MPC renunciation, the Wharton Rule, and the protected class exception—and when each actually bars a conspiracy conviction
Practical strategies for parsing multi-party fact patterns, isolating each agreement, and determining which parties can be convicted of conspiracy, the target crime, both, or neither under MBE-style rules

MBE Syllabus

For the MBE, you are required to understand the law of inchoate crimes, with particular focus on conspiracy, with a focus on the following syllabus points:

Recognize the elements required to establish conspiracy: agreement, intent to agree, intent to achieve the unlawful objective, and (where required) an overt act
Distinguish conspiracy from attempt and solicitation, and understand how these inchoate offenses interact
Identify when and how parties are liable for substantive offenses committed by co-conspirators (Pinkerton liability)
Apply the rules regarding withdrawal, renunciation, and other defenses to conspiracy
Understand the impact of the Wharton Rule, the protected class exception, unilateral vs. bilateral approaches, and chain vs. spoke-hub conspiracies
Know that conspiracy generally does not merge with the completed offense, unlike attempt and solicitation

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

Which of the following is NOT required for a common law conspiracy?
1. An agreement between two or more persons
2. Intent to achieve the unlawful objective
3. An overt act in furtherance of the conspiracy
4. Intent to agree
Under the modern approach, a conspirator is liable for which crimes committed by co-conspirators?
1. Only crimes he personally commits
2. All foreseeable crimes committed in furtherance of the conspiracy
3. Only the target offense
4. Only crimes committed after he joins the conspiracy
Which of the following is a valid defense to conspiracy?
1. Withdrawal before the agreement is made
2. Factual impossibility
3. Withdrawal before the overt act (in some jurisdictions)
4. Legal impossibility
Under the Model Penal Code, can a defendant be convicted of conspiracy if the only other party is an undercover police officer?
1. Yes
2. No

Introduction

Conspiracy is a central inchoate crime tested on the MBE. It involves an agreement to commit a criminal offense (or to use criminal means to achieve a lawful objective) and is unique because liability attaches even before the planned crime is attempted or completed. Conspiracy also expands criminal responsibility: a person who joins a conspiracy may be liable not only for the agreement itself but also for crimes committed by other conspirators.

Understanding the elements, the scope of co-conspirator liability, and the available defenses is essential to handling MBE criminal law questions.

Key Term: Inchoate Crime
An offense involving steps toward the commission of another crime, but where the ultimate crime has not yet occurred. Includes attempt, solicitation, and conspiracy.

On the MBE, conspiracy is often tested alongside attempt and solicitation. A useful shorthand is:

Solicitation: asking or encouraging another to commit a crime
Conspiracy: agreeing with another to commit a crime
Attempt: taking a substantial step toward committing the crime

Conspiracy stands out because:

It is complete once the agreement (and, in most jurisdictions, an overt act) occurs, even if the target crime never happens
It does not merge with the completed offense; a defendant can be convicted of both conspiracy and the substantive crime
It can generate liability for additional crimes committed by co-conspirators in furtherance of the plan

Elements of Conspiracy

At common law, conspiracy consists of an agreement between two or more persons to commit an unlawful act, combined with the specific intent to achieve that act. Most modern statutes and the federal system also require an overt act in furtherance of the conspiracy.

Many modern formulations describe conspiracy as an agreement to commit a crime or to accomplish a lawful objective by unlawful (criminal) means.

Agreement

The heart of conspiracy is an agreement to pursue a criminal objective.

Key Term: Agreement (Conspiracy)
An express or implied understanding between at least one person with criminal intent and another to pursue a shared unlawful objective (or a lawful objective by unlawful means).

The agreement:

May be express (spoken or written) or implied from conduct
Does not require formalities; juries may infer agreement from coordinated actions over time
Requires that the parties agree to accomplish the same unlawful objective by mutual action

Mere knowledge that a crime will occur and passive approval are not enough. Simply being present at the scene, or cheering others on, does not create conspirator status without a true agreement.

For example, a person who applauds a bar fight is not a conspirator merely for cheering; there must be some understanding to participate in or support the crime.

The object of the agreement also matters:

Modern view: the object generally must be a crime, or a lawful objective to be achieved by criminal means
At common law: the object needed only to be “unlawful,” which could include noncriminal acts against public welfare, but the MBE primarily focuses on criminal objectives

If what the parties plan to do is not actually a crime, there is no conspiracy, even if they mistakenly believe it is criminal (this relates to legal impossibility, discussed below).

Key Term: Conspiracy
An agreement between two or more persons (under common law) or at least one person with criminal intent (under the MPC) to commit a criminal offense or achieve a lawful objective by unlawful means, with intent to achieve the unlawful objective.

Intent

Conspiracy is a specific intent crime. Each conspirator must have two distinct intents:

Intent to enter into the agreement; and
Intent that the unlawful objective of the conspiracy be achieved.

Key Term: Specific Intent
The mental state where the defendant intends both the conduct and the result required by the offense.

Important points for the MBE:

The intent to agree can be inferred from conduct (e.g., repeatedly participating in the group’s plan)
Heavier focus is on the intent to achieve the objective. Each defendant must personally intend the target offense

Illustration: A, B, and C agree to take D’s car. A and B intend to keep it permanently; C believes they will borrow it and return it. Only A and B are guilty of conspiracy to commit larceny, because only they intend a permanent deprivation.

Mere knowledge is insufficient:

A merchant who sells ordinary goods, knowing the buyer will use them in a crime, is not automatically a conspirator
Intent may be inferred if the seller:
- Supplies a special or hard-to-get item with no obvious lawful use; or
- Charges a premium or otherwise shows a “stake” in the criminal venture

Strict liability offenses: conspiracy still requires specific intent. For example, statutory rape may be a strict liability crime as to age, but conspiracy to commit statutory rape generally requires knowledge (or belief) that the victim is underage.

A minority of jurisdictions apply a “corrupt motive” doctrine to some regulatory offenses (malum prohibitum), requiring awareness that the plan is illegal. For MBE purposes, assume this doctrine applies only if the question explicitly mentions it.

Overt Act

At common law, no overt act was required; the conspiracy was complete once the agreement was made with the requisite intent. Many modern statutes, including the federal system and the Model Penal Code, add a fourth element: an overt act in furtherance of the conspiracy.

Key Term: Overt Act
Any act, however minor, taken by any conspirator to help accomplish the objective of the conspiracy.

Key points:

The overt act may be lawful or unlawful (e.g., renting a car, buying masks, joining a gym to get stronger for an attack)
The act can be very minor and may be mere preparation
It need not itself be a crime
It can be done by any one conspirator and counts for all

This is easier to satisfy than the “substantial step” required for attempt. For attempt, the defendant must move beyond mere preparation; for conspiracy, any step in furtherance of the agreed plan is enough if an overt act is required.

Exam tip: Unless the question specifies “MPC,” “modern majority,” or a statute requiring an overt act, apply the common law rule that no overt act is needed to complete the conspiracy.

Scope of Liability

Conspiracy dramatically expands criminal liability beyond the conspirator’s own acts.

Liability for the Conspiracy and the Target Offense

Conspiracy is separate from the completed crime. Modernly:

Conspiracy does not merge with the completed offense
A defendant may be convicted of both conspiracy and the substantive offense
Attempt and solicitation, by contrast, usually merge into the completed crime (and sometimes into conspiracy)

Rationale: Group criminal activity is considered especially dangerous because it combines planning and mutual reinforcement.

Pinkerton Rule

A central feature of conspiracy on the MBE is liability for crimes committed by co-conspirators.

Key Term: Pinkerton Liability
The doctrine that holds each conspirator liable for substantive crimes committed by other conspirators if those crimes were committed in furtherance of the conspiracy and were reasonably foreseeable.

Under the Pinkerton rule (followed in many jurisdictions):

A conspirator is liable for a co-conspirator’s substantive crime if:

The crime was committed in furtherance of the objectives of the conspiracy;
The crime was a natural and probable consequence of the conspiracy (reasonably foreseeable); and
The defendant was a member of the conspiracy at the time (had not effectively withdrawn).

Example (adapted): Goldie, Frank, and Myrtle agree to steal goods from a sporting goods store. Goldie goes inside; Frank acts as lookout; Myrtle drives the getaway car. When a security guard approaches, Frank panics and shoves the guard, who breaks his arm. Goldie exits with goods, including starter pistols. Later, Myrtle uses a starter pistol to rob a convenience store.

All three are liable for conspiracy and for the theft from the sporting goods store
Goldie and Frank are liable for battery of the guard (committed in furtherance of the theft and foreseeable)
Myrtle is not liable for the later convenience store robbery; that crime was not in furtherance of the original conspiracy, and Goldie and Frank did not agree to it

Note: Some jurisdictions reject Pinkerton as too broad and instead require traditional accomplice liability (intent to aid the specific substantive crime). Unless told otherwise, assume the jurisdiction follows Pinkerton on the MBE.

Relationships Among Co-Conspirators: Chain vs. Spoke-Hub

The structure of the conspiracy can affect the scope of Pinkerton liability.

Key Term: Chain Conspiracy
A single, large conspiracy in which each participant plays a role in a linked series of steps toward a common unlawful objective (e.g., manufacturer–wholesaler–dealer in a drug distribution scheme).

Key Term: Spoke-Hub Conspiracy
A pattern in which a central figure (the “hub”) separately agrees with multiple others (the “spokes”), but there is no agreement among the spokes themselves to participate in a single common scheme.

Chain conspiracy example: A drug manufacturer sells to a distributor, who sells to street dealers. Even if the manufacturer never meets the street dealer, they are all part of one conspiracy and can be liable for each other’s foreseeable crimes in furtherance of the drug operation.
Spoke-hub example: A bank employee (hub) agrees with several customers (spokes) to process fraudulent loans. Each customer has a separate agreement with the employee, but not with other customers. Each spoke is generally responsible only for his own conspiracy with the hub, not for the misdeeds of other spokes, absent evidence of a broader shared plan.

On the MBE, recognizing chain vs. spoke-hub helps you determine whether one conspirator is liable for crimes committed by a more distant participant.

Termination of a Conspiracy

A conspiracy continues until:

The objectives are achieved, or
The conspirators abandon their efforts

Acts of concealment:

Ordinary acts to hide the crime (e.g., lying to police) do not extend the conspiracy unless the conspirators specifically agreed, at the outset, to engage in such concealment as part of their plan
This matters for statute of limitations and for the admission of co-conspirator statements (they are admissible only if made during and in furtherance of the conspiracy)

Government frustration of the conspiracy’s objective (such as intercepting drugs before delivery) does not automatically terminate the conspiracy, and impossibility resulting from government action is not a defense to the conspiracy charge.

Scope of Liability: Withdrawal

Withdrawal does not undo a conspiracy that has already formed, but it can limit future liability.

Key Term: Withdrawal (Conspiracy)
An affirmative act by a conspirator to end participation in the conspiracy, which may limit liability for future crimes committed in furtherance of the conspiracy but generally does not erase liability for the conspiracy itself.

Common law:

It is not possible to withdraw from the conspiracy offense once the agreement is made (and overt act if required); the crime is already complete
However, a conspirator can withdraw to avoid liability for later substantive crimes committed by co-conspirators

Modern and MPC approaches distinguish between:

Withdrawal to cut off future Pinkerton liability, and
Renunciation as a potential defense to the conspiracy itself (in some MPC-style jurisdictions)

To cut off liability for future crimes, most jurisdictions require:

An affirmative act that clearly communicates withdrawal to all other conspirators, and
Communication made in time for them to abandon the plan

If the withdrawing conspirator also aided the plan (e.g., supplied weapons), some jurisdictions require an attempt to neutralize the prior assistance (e.g., retrieving the weapon or warning the intended victim).

MPC renunciation:

Under the MPC, a conspirator can have a defense to the conspiracy itself if he voluntarily and completely renounces his criminal purpose and thwarts, or attempts to thwart, the success of the conspiracy (commonly by notifying law enforcement in time).

On the MBE, unless the question specifically discusses MPC renunciation, assume that withdrawal:

Does not bar conviction for conspiracy once formed; but
Does cut off Pinkerton liability for subsequent crimes if properly communicated and timely.

Special Doctrines

Unilateral vs. Bilateral Conspiracy

Key Term: Unilateral Conspiracy
A conspiracy where only one party actually intends to commit the crime; the other may be feigning agreement (e.g., an undercover officer).

Key Term: Bilateral Conspiracy
A conspiracy requiring at least two parties with genuine criminal intent to agree to commit the crime.

Traditional common law (bilateral approach):

Requires at least two “guilty minds” genuinely agreeing to the unlawful plan
If one party is feigning agreement (e.g., undercover officer), there is no conspiracy
Consequences:
- If all alleged co-conspirators are later acquitted, the remaining defendant cannot be convicted of conspiracy in many bilateral jurisdictions

Modern trend and MPC (unilateral approach):

Only the defendant must have true criminal intent
The other “conspirator” may be an undercover officer or someone who lacks criminal capacity
The defendant may still be convicted of conspiracy even if the other party can never be convicted

Exam tip: Unless the question states “MPC,” “modern majority,” or “unilateral” approach, apply the common law bilateral rule as the default.

Wharton Rule

Key Term: Wharton Rule
A limitation providing that where the predicate crime by definition requires two participants, there is no separate conspiracy unless more parties participate than are required for the substantive offense.

If the target offense necessarily requires the participation of two people (e.g., adultery, dueling, incest, bigamy), the Wharton Rule generally bars conspiracy charges when only the minimum number of participants are involved.

Example: Two people agree to duel. Because dueling inherently requires two participants, there is no separate conspiracy under the Wharton Rule unless a third person joins in a way that expands the scheme.

Limitations:

The rule does not apply when the statute contemplates “necessary parties not provided for” in the offense. For instance, if a statute punishes only the seller of narcotics, the buyer and seller may still be guilty of conspiracy to sell narcotics because the buyer is not a party “required” by the statute.
Some courts treat the Wharton Rule as barring any conspiracy conviction; others allow conviction for conspiracy or the substantive crime, but not both.

Protected Class Exception

Key Term: Protected Class Exception
A person within the class the law is designed to protect cannot be convicted of conspiracy to violate that law.

If a statute is designed to protect a particular class of persons, a member of that class:

Cannot be guilty of the substantive offense (e.g., the underage participant in statutory rape)
Cannot be guilty of conspiracy to violate the statute
Consequently, there may be no conspiracy at all in a bilateral jurisdiction because there is no second “guilty” party

Examples:

Statutory rape: A minor cannot conspire with an adult to commit statutory rape where the statute exists to protect minors.
Mann Act–type transport statute: A woman transported across state lines for immoral purposes is within the protected class and cannot be a conspirator to violate that statute.

This exception also applies to accomplice liability: a protected party cannot be an accomplice to a violation of a statute intended for her protection.

Defenses and Limitations to Conspiracy

In addition to withdrawal and the special doctrines above, several other doctrines limit conspiracy liability.

Impossibility

Key Term: Legal Impossibility
A defense arising when the parties intend to commit an act they believe is criminal, but the act is not actually a crime; even if carried out as planned, no law would be violated.

Key Term: Factual Impossibility
A situation in which the intended criminal result is impossible to achieve due to facts unknown to the defendant (e.g., the “victim” is already dead or the “drugs” are sugar), although the conduct would be criminal if the facts were as the defendant believed.

Factual impossibility is not a defense to conspiracy. If the parties agreed to commit what would be a crime under the facts as they believed them, they are guilty of conspiracy even if completion was impossible.
Legal impossibility can be a defense: if the objective is not actually criminal, there is no conspiracy, because there is no “unlawful” objective.

Example of legal impossibility: Two people agree to catch eggs from a bird they mistakenly believe to be an endangered species, thinking it is illegal to take the eggs. If that bird is not protected, their plan is not a crime, and there is no conspiracy.

Withdrawal (Revisited)

Not a defense to the existence of a common law conspiracy once complete
Can be a defense to the conspiracy itself under MPC-style renunciation (only if the conspirator thwarts or tries to thwart the conspiracy)
Can limit liability for future substantive offenses if properly communicated and timely, as discussed above

Merger

Conspiracy does not merge with the completed offense; a defendant may be convicted of both conspiracy and the substantive crime
Attempt and solicitation generally merge into the completed offense
Solicitation may also merge into conspiracy when the solicitation leads to an agreement; many jurisdictions treat conspiracy as absorbing the initial solicitation

Other Limitations

In bilateral jurisdictions, acquittal of all other alleged conspirators ordinarily bars conviction of the remaining defendant
However, dropping charges against others (e.g., via plea bargains) does not prevent conviction of the remaining conspirator
A defendant’s presence at trial or arrest before the target offense is committed does not prevent conviction for conspiracy; the offense lies in the agreement and overt act, not physical participation at the crime scene

Worked Example 1.1

Scenario: Alice and Ben agree to rob a bank. Alice buys masks; Ben rents a car. Before the robbery, Alice tells Ben she wants out and notifies the police. Ben proceeds and robs the bank.

Answer:
Both Alice and Ben are guilty of conspiracy once they agreed and an overt act occurred (buying masks, renting the car). Alice’s later withdrawal does not erase the conspiracy. However, by clearly withdrawing and notifying both Ben and the police in time, she cuts off Pinkerton liability for the subsequent bank robbery. Thus, Alice is guilty of conspiracy but not of the robbery itself; Ben is guilty of both.

Worked Example 1.2

Scenario: Carl and Dave agree to sell illegal drugs. Dave is an undercover officer who never intends to commit the crime.

Answer:
Under the MPC’s unilateral approach, Carl can be convicted of conspiracy because he had the requisite intent and believed he was agreeing to engage in drug dealing, even though Dave lacked criminal intent. Under the traditional bilateral approach, there is no conspiracy because there is no true agreement between two guilty parties; Carl may still be guilty of solicitation or attempt, depending on his conduct.

Worked Example 1.3

Scenario: Eva and Frank agree to burglarize a warehouse. The next day, Frank buys a crowbar, intending to use it to break in. They are arrested before going to the warehouse. The jurisdiction follows the majority rule requiring an overt act for conspiracy and also criminalizes attempted burglary.

Answer:
The agreement plus Frank’s purchase of the crowbar (an act in furtherance) satisfies the overt act requirement for conspiracy. Both Eva and Frank can be convicted of conspiracy even though only Frank acted. However, buying a crowbar is likely mere preparation, not a “substantial step” toward burglary, so they cannot be convicted of attempt.

Worked Example 1.4

Scenario: A chemical supplier sells large quantities of a precursor chemical to a group that manufactures illegal drugs. The supplier knows the group’s purpose. The substance has many lawful industrial uses. The supplier charges ordinary market prices and does not otherwise participate in the scheme.

Answer:
Mere knowledge that goods will be used in a crime is not enough to make the supplier a conspirator. The chemical has lawful uses, and there is no evidence of a special stake in the venture (no markup, no close coordination). Absent additional facts suggesting intent to further the conspiracy (such as supplying only drug makers, giving advice on avoiding detection, or charging an inflated price), the supplier is not part of the conspiracy.

Worked Example 1.5

Scenario: A central “fence” buys stolen goods from several unrelated thieves and resells them. Each thief independently agrees with the fence to sell stolen property. The thieves never meet and have no knowledge of one another.

Answer:
The fence has separate conspiracies with each thief (spoke-hub pattern). There is no single overarching conspiracy involving all thieves because there is no agreement among the spokes to participate in a common scheme. Thus, Thief 1 is not liable for crimes committed by Thief 2 or Thief 3 under Pinkerton; each is liable only for the conspiracy and thefts tied to their own agreement with the fence.

Exam Warning

On the MBE, be alert for questions where one party is an undercover officer. Determine whether the jurisdiction follows the unilateral (MPC) or bilateral (common law) approach. Also, be careful to distinguish the minimal overt act required for conspiracy from the substantial step required for attempt.

Revision Tip

Remember: Withdrawal is not a defense to conspiracy once the agreement (and any required overt act) has occurred, but it may shield a defendant from liability for substantive crimes committed by co-conspirators after effective, timely withdrawal.

Summary

Conspiracy is an inchoate offense that punishes the agreement to commit a crime, not just the crime itself. It generally requires:

An agreement (express or implied)
Specific intent both to agree and to achieve the unlawful objective
In most modern jurisdictions, an overt act in furtherance of the plan

Conspiracy is distinctive in that:

It does not merge with the completed offense; a defendant may be convicted of both
Pinkerton liability can make conspirators responsible for additional crimes committed by others if those crimes are in furtherance of the conspiracy and reasonably foreseeable
Withdrawal does not undo the conspiracy once formed, but can cut off liability for future substantive crimes
Special doctrines such as the unilateral vs. bilateral approaches, the Wharton Rule, and the protected class exception can prevent or shape conspiracy liability
Factual impossibility is not a defense; legal impossibility may be, where the planned conduct is not actually criminal

A solid understanding of these rules, and of how conspiracy compares with attempt and solicitation, is essential for resolving MBE questions involving group criminal activity and expanded liability.

Key Point Checklist

This article has covered the following key knowledge points:

Conspiracy is an inchoate offense based on an agreement to commit a crime or achieve a lawful objective by unlawful means
Elements: agreement, intent to agree, intent to achieve the unlawful objective, and (in most jurisdictions) an overt act by any conspirator
The agreement can be express or implied; mere knowledge or passive presence is insufficient
Conspiracy is a specific intent crime; each defendant must personally intend the unlawful objective
The overt act requirement is minimal and can be satisfied by conduct that is only preparatory, unlike attempt’s “substantial step” requirement
Under Pinkerton, conspirators are liable for reasonably foreseeable crimes committed in furtherance of the conspiracy by co-conspirators, as long as they have not effectively withdrawn
Chain conspiracies create broad liability among participants; spoke-hub conspiracies generally limit liability between spokes
Withdrawal does not erase the conspiracy once formed but can cut off liability for later substantive offenses if properly and timely communicated
The MPC allows unilateral conspiracy; common law requires bilateral conspiracy with at least two guilty parties
The Wharton Rule bars separate conspiracy liability for offenses that inherently require two participants, unless more than the necessary number participate
The protected class exception prevents members of a protected class from being conspirators or accomplices to statutes designed for their protection
Factual impossibility is not a defense to conspiracy; legal impossibility (no actual crime) can be
Conspiracy does not merge with the completed offense; a defendant can be convicted of both conspiracy and the target crime

Key Terms and Concepts

Inchoate Crime
Conspiracy
Agreement (Conspiracy)
Specific Intent
Overt Act
Pinkerton Liability
Withdrawal (Conspiracy)
Unilateral Conspiracy
Bilateral Conspiracy
Wharton Rule
Protected Class Exception
Chain Conspiracy
Spoke-Hub Conspiracy
Legal Impossibility
Factual Impossibility

Inchoate crimes; parties - Conspiracy