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 Hawaii, criminal conspiracy is addressed under Hawaii Revised Statutes Section 705-520. Similar to federal law, a criminal conspiracy in Hawaii involves an agreement between two or more persons to commit a crime, with at least one overt act taken to further the conspiracy. The state's interest in prosecuting conspiracies aligns with the dual purposes of combating the collaborative efforts to commit crimes and enabling the prosecution of individuals who contribute to the planning of a crime without necessarily committing the physical act. The severity of the punishment for conspiracy in Hawaii typically depends on the nature of the crime that the conspirators intended to commit. For instance, if the conspiracy was to commit a felony, the charge for conspiracy will also be a felony, often one class lower than the most serious crime that is the object of the conspiracy. This allows the state to impose significant penalties on those involved in the planning stages of criminal activity, even if the underlying crime was not completed.