The crime of “conspiracy” is simple enough in theory. It’s a crime to plan with other people to engage in criminal activity. The details of the law, however, can be complex and nuanced. When does “just talk” turn into a concrete enough plan to become punishable? Are there free speech implications of punishing “talk”? How far does a plot have to go before it morphs into a “conspiracy”? These are some of the many complex questions that permeate this area of law.
Punishing conspiracy is designed to deter potential criminals from becoming organized and to ensure that all those who had active parts in criminal activity are held accountable.
Conspiracy, like attempt and criminal solicitation, is an inchoate crime. This means that the criminal result need not have occurred for liability to attach. If two people, for example plan the joint robbery of a store, they can be liable for conspiracy even if they do not complete the robbery. The substantive crime is robbery and conspiracy to commit robbery is inchoate because it has not been completed.
The law treats the act of agreeing to commit a crime as “a distinct evil” from the crime itself. This means that a defendant can be charged with both conspiracy to commit a crime and the crime that was completed. This distinction can be illustrated by comparing conspiracy to another inchoate crime, attempt. When a person attempts to commit a crime and then successfully completes that crime, the two crimes “merge” and the defendant can only be charged with the completed crime. Merger does not occur in conspiracy cases.
For example, let’s assume that Kyle and Sue decide to murder Charlie. They conspire ahead of time to ambush Charlie in a parking lot after work and stab him to death. They are guilty of conspiracy to commit murder whether they complete the crime or not. Conversely, if their attempt was a spur-of-the-moment decision and not a product of prior deliberation, and Charlie survives the assault, they would be guilty of attempted murder but not conspiracy to commit murder. If their attempt succeeds in the latter scenario, they would be guilty of murder but not attempted murder.
The modern elements of conspiracy are:
(1) An agreement;
(2) Between two or more people;
(3) That is entered into for the purpose of committing a crime; and
(4) An overt act is made in furtherance of the conspiracy.
Agreement of Two or More Parties
The agreement is the most important element of a conspiracy. In some jurisdictions, to be charged with conspiracy, all that is required is to form an agreement to commit a crime.
The agreement does not need to be formal or an in-depth plan and its existence can be inferred from the circumstances. This has had the effect of allowing courts to find a conspiracy from the circumstances surrounding the completed crime even if there is no evidence of actual verbalization or paper trail of the plot. Note that even if the underlying goal of the agreement cannot be accomplished because it is physically impossible, the defendants can still be charged with conspiracy. So, for example, if two parties conspire to rob a store that, unbeknownst to them, has permanently closed, they can still be held liable for conspiracy.
In the United States, it is universally accepted that at least two people are needed to form a conspiracy. However, there is a split on whether both parties must have guilty minds.
Under the “rule of consistency” or the “bilateral” approach, there must be two guilty minds. Both parties to the conspiracy must sincerely agree to commit the crime. In a two-person conspiracy, if one co-conspirator is acquitted, then the other co-conspirator cannot be guilty of conspiracy. Without an agreement, there can be no conspiracy. However, this applies only when two alleged co-conspirators are tried for the same crime in the same trial for the same conspiracy. If one is acquitted, perforce, the other must be acquitted as well as a conspiracy requires at least two guilty participants. If they are tried separately and the first co-conspirator is acquitted or is never charged, then the second co-conspirator can still be charged with conspiracy. After all, the evidence may be stronger against one person than the other or different juries might not read the evidence in the same manner. That one is acquitted does not necessarily mean that there is insufficient evidence that they both conspired for purposes of convicting the second conspirator.
Under the unilateral approach, which was adopted by the Model Penal Code and some of the states, only one person needs to have a guilty mind. So, for example, a person can be guilty of conspiracy even if the other party is an undercover police officer or other party that has no intention of carrying out the criminal actions contemplated.
Most jurisdictions require that, in addition to agreeing to commit a crime, at least one member of the conspiracy must take an action in furtherance of the illegal objective. This requirement of an “overt act” serves to distinguish mere talk from a plan that contemplates the performance of illegal activity. Typically, any act taken in furtherance of the conspiracy will be sufficient, but some states requires that the defendant take a more substantial step.
Let’s return to Kyle, Sue, and Charlie. Kyle and Sue have decided to kill Charlie. Kyle and Sue spend hours planning how they are going to kill Charlie. So far (in most jurisdictions), they are not yet guilty of conspiracy. After all, to overcome a potential defense argument that they were merely talking or describing what they wish might happen would not be easy. Now, however, assume that Sue goes out and buys a pair of sharp steak knives with which to commit the crime. It is now apparent that the planning was more than mere talk. Sue’s “overt act” demonstrates the seriousness of the plan and both Kyle and Sue could be held liable for conspiracy to commit murder.
Object of the Agreement
Most jurisdictions require a specific illegal object for there to be the crime of conspiracy. However, some states make it a crime to conspire even to perform legal activities, where the object of the plan is to engage in behavior that would be harmful to the public health. An example of this would be a conspiracy to run a loan shark business. While it may not be a statutory criminal act to lend money to people at high interest rates, running a loan shark operation may be considered injurious the public health. Thus, the planning of this venture could be considered the crime of conspiracy in some jurisdictions.
Required Mental State
Conspiracy is a specific intent crime. Specific intent crimes require that the defendant act with a specific goal in mind. In the case of conspiracy, the defendant must intend to agree on a plan to commit an act and must intend to achieve the illegal goal of the conspiracy. If either of these intents is missing, then the defendants cannot be charged with conspiracy.
Let’s return to the Kyle and Sue example one last time. Kyle and Sue agree to kill Charlie. Kyle hates Charlie and really intends to murder him. Sue, on the other hand, believes it is all a joke. She thinks that they are just going to scare Charlie, but that they won’t hurt him in any way. Since Sue does not intend to commit the underlying offense of murder, she cannot be charged with conspiracy. Kyle could be charged with conspiracy only if the jurisdiction subscribes to the “unilateral” approach discussed earlier, which requires only a single guilty mind in a conspiracy.
To sum up, while conspiracy is a complex crime, the common denominator is that criminal conspiracies require agreements, intent to agree, intent to accomplish an illegal objective and, usually, at least one overt act in furtherance of the conspiracy.
 Paul Marcus, Prosecution and Defense of Criminal Conspiracy Cases, § 1.04 (Matthew Bender, Rev. Ed.)
 Martin H. Pritikin, Toward Coherence in Civil Conspiracy Law: A Proposal to Abolish the Agent's Immunity Rule, 84 Neb. L. Rev. 1, 6-7 (2005).
 See Berry v. State, 996 So.2d 782 (2008).
 Id. at § 1.03 and 2.01.
 Paul Marcus, Prosecution and Defense of Criminal Conspiracy Cases, § 2.02 (Matthew Bender, Rev. Ed.).
 Paul Marcus, Prosecution and Defense of Criminal Conspiracy Cases, § 2.03 (Matthew Bender, Rev. Ed.).
 Model Penal Code § 5.03.
 Id. at § 2.09