Conspiracy is set forth in N.J.S. 2C:5-2.

2C:5-2. Conspiracy.

     2C:5-2. Conspiracy. a. Definition of conspiracy. A person is guilty of conspiracy with another person or persons to commit a crime if with the purpose of promoting or facilitating its commission he:

     (1)     Agrees with such other person or persons that they or one or more of them will engage in conduct which constitutes such crime or an attempt or solicitation to commit such crime; or

     (2)     Agrees to aid such other person or persons in the planning or commission of such crime or of an attempt or solicitation to commit such crime.

     b.     Scope of conspiratorial relationship. If a person guilty of conspiracy, as defined by subsection a. of this section, knows that a person with whom he conspires to commit a crime has conspired with another person or persons to commit the same crime, he is guilty of conspiring with such other person or persons, whether or not he knows their identity, to commit such crime.

     c.     Conspiracy with multiple objectives. If a person conspires to commit a number of crimes, he is guilty of only one conspiracy so long as such multiple crimes are the object of the same agreement or continuous conspiratorial relationship. It shall not be a defense to a charge under this section that one or more of the objectives of the conspiracy was not criminal; provided that one or more of its objectives or the means of promoting or facilitating an objective of the conspiracy is criminal.

     d.     Overt act. No person may be convicted of conspiracy to commit a crime other than a crime of the first or second degree or distribution or possession with intent to distribute a controlled dangerous substance or controlled substance analog as defined in chapter 35 of this title, unless an overt act in pursuance of such conspiracy is proved to have been done by him or by a person with whom he conspired.

     e.     Renunciation of purpose. It is an affirmative defense which the actor must prove by a preponderance of the evidence that he, after conspiring to commit a crime, informed the authority of the existence of the conspiracy and his participation therein, and thwarted or caused to be thwarted the commission of any offense in furtherance of the conspiracy, under circumstances manifesting a complete and voluntary renunciation of criminal purpose as defined in N.J.S.2C:5-1d.; provided, however, that an attempt as defined in N.J.S.2C:5-1 shall not be considered an offense for purposes of renunciation under this subsection.

     f.     Duration of conspiracy. For the purpose of N.J.S.2C:1-6d.:

     (1)     Conspiracy is a continuing course of conduct which terminates when the crime or crimes which are its object are committed or the agreement that they be committed is abandoned by the defendant and by those with whom he conspired; and

     (2)     Such abandonment is presumed with respect to a crime other than one of the first or second degree if neither the defendant nor anyone with whom he conspired does any overt act in pursuance of the conspiracy during the applicable period of limitation; and

     (3)     If an individual abandons the agreement, the conspiracy is terminated as to him only if and when he advises those with whom he conspired of his abandonment or he informs the law enforcement authorities of the existence of the conspiracy and of his participation therein.

     g.     Leader of organized crime. A person is a leader of organized crime if he purposefully conspires with others as an organizer, supervisor, manager or financier to commit a continuing series of crimes which constitute a pattern of racketeering activity under the provisions of N.J.S. 2C:41-1, provided, however, that notwithstanding 2C:1-8a. (2), a conviction of leader of organized crime shall not merge with the conviction of any other crime which constitutes racketeering activity under 2C:41-1. As used in this section, "financier" means a person who provides money, credit or a thing of value with the purpose or knowledge that it will be used to finance or support the operations of a conspiracy to commit a series of crimes which constitute a pattern of racketeering activity, including but not limited to the purchase of materials to be used in the commission of crimes, buying or renting housing or vehicles, purchasing transportation for members of the conspiracy or otherwise facilitating the commission of crimes which constitute a pattern of racketeering activity.

Conspiracy has been defined in the US as an agreement of two or more people to commit a crime, or to accomplish a legal end through illegal actions. For example, planning to rob a bank (an illegal act) to raise money for charity (a legal end) remains a criminal conspiracy because the parties agreed to use illegal means to accomplish the end goal. A conspiracy does not need to have been planned in secret to meet the definition of the crime. One legal dictionary, law.com, provides this useful example on the application of conspiracy law to an everyday sales transaction tainted by corruption. It shows how the law can handle both the criminal and the civil need for justice.

[A] scheme by a group of salesmen to sell used automobiles as new, could be prosecuted as a crime of fraud and conspiracy, and also allow a purchaser of an auto to sue for damages [in civil court] for the fraud and conspiracy.

Conspiracy law usually does not require proof of specific intent by the defendants to injure any specific person to establish an illegal agreement. Instead, usually the law only requires the conspirators have agreed to engage in a certain illegal act. This is sometimes described as a "general intent" to violate the law.

In United States v. Shabani, 513 U.S. 10 (1994) the United States Supreme Court ruled: U.S. Congress intended to adopt the common law definition of conspiracy, which does not make the doing of any act other than the act of conspiring a condition of liability" at least insofar as to establish a violation of a narcotics conspiracy under U.S.C. § 846. Therefore, the Government need not prove the commission of any overt acts in furtherance of those narcotics conspiracies prohibited by 21 U.S.C. § 846. The Shabani case illustrates that it is a matter of legislative prerogative whether to require an overt step, or not to require an overt step in any conspiracy statute. The court compares the need to prove an overt step to be criminally liable under the conspiracy provision of the Organized Crime Control Act of 1970, while there is no such requirement under 21 U.S.C. § 846.

The Supreme Court pointed out that common law did not require proof of an overt step, and the need to prove it for a federal conspiracy conviction requires Congress to specifically require proof of an overt step to accomplish the conspiracy. It is a legislative choice on a statute by statute basis.

The conspirators can be guilty even if they do not know the identity of the other members of the conspiracy. See United States v. Monroe, 73 F.3d 129 (7th Cir. 1995), aff'd., 124 F.3d 206 (7th Cir. 1997).

One important feature of a conspiracy charge is that it relieves prosecutors of the need to prove the particular roles of conspirators. If two persons plot to kill another (and this can be proven), and the victim is indeed killed as a result of the actions of either conspirator, it is not necessary to prove with specificity which of the conspirators actually pulled the trigger. (Otherwise, both conspirators could conceivably handle the gun—leaving two sets of fingerprints—and then demand acquittals for both, based on the fact that the prosecutor would be unable to prove beyond a reasonable doubt, which of the two conspirators was the triggerman). A conspiracy conviction requires proof that a) the conspirators did indeed conspire to commit the crime, and b) the crime was committed by an individual involved in the conspiracy. Proof of which individual it was is usually not necessary.

It is also an option for prosecutors, when bringing conspiracy charges, to decline to indict all members of the conspiracy (though their existence may be mentioned in an indictment). Such unindicted co-conspirators are commonly found when the identities or whereabouts of members of a conspiracy are unknown; or when the prosecution is only concerned with a particular individual among the conspirators. This is common when the target of the indictment is an elected official or an organized crime leader; and the co-conspirators are persons of little or no public importance. More famously, President Richard Nixon was named as an unindicted co-conspirator by the Watergate special prosecutor, in an event leading up to his eventual resignation.