A criminal conspiracy is generally a partnership formed to commit a crime or crimes. A criminal conspiracy exists when two or more persons form an agreement to violate a law that includes criminal penalties, and then take one or more steps designed to accomplish the goal of the conspiracy.

Federal and state statutes make criminal conspiracies illegal for two primary purposes: (1) to help combat the powerful forces created when two or more people collaborate to commit a crime; and (2) to allow criminal prosecutors (state and federal) to prosecute persons who play a role in planning a crime but who are not involved in the physical acts taken to complete the underlying crime.

For example, under federal law, if two or more persons conspire either to commit any offense against the United States, or to defraud the United States, or any agency of the United States in any manner or for any purpose, and one or more of such persons do any act to accomplish the objective of the conspiracy, each of the conspirators may be fined under and imprisoned for up to five years. See 18 U.S.C. §371. And most states have statutes (usually located in the penal or criminal code) that make criminal conspiracies a crime and include significant punishment upon conviction.

In Michigan, criminal conspiracy is recognized as a serious offense and is defined as an agreement between two or more persons to commit a criminal act or to accomplish a legal act by unlawful means. The state requires that at least one overt act in furtherance of the conspiracy be taken, although the act itself does not need to be illegal. This is in line with the dual purposes of conspiracy laws: to dismantle the collaborative efforts to commit crimes and to hold accountable those involved in the planning stages of criminal activities, even if they do not participate in the execution of the crime itself. Under Michigan law, the penalties for conspiracy align with the penalties for the intended crime, meaning that if the target offense is a felony, the conspiracy will be treated as such, with corresponding punishments. This is similar to federal law, specifically 18 U.S.C. §371, which also criminalizes conspiracy to commit any offense against the United States or to defraud the United States, with penalties including fines and imprisonment for up to five years. Both state and federal statutes thus provide prosecutors with the means to charge individuals who are involved in the preparatory phases of criminal endeavors.