What is the Conspiracy Law in Illinois?

The crime of conspiracy is one of very few crimes that are punishable without actually having committed the plotted crime.  This type of crime is called an inchoate crime.  Other types of inchoate offenses are solicitation and attempt.  There are different theories about what makes a conspiracy.  Some jurisdictions require an overt act in furtherance of the conspiracy to seal the deal.  Other states won’t find a conspiracy if one of the participants is an undercover police officer.

Illinois Statute 720 ILCS 5/8-2 defines conspiracy as follows:

“A person commits the offense of conspiracy when, with intent that an offense be committed, he or she agrees with another to the commission of that offense.  No person may be convicted of conspiracy to commit an offense unless an act in furtherance of that agreement is alleged and proved to have been committed by him or her by a co-conspirator.”

The language of this statute sets out the different elements of the crime that must be proven, which are intent, a plan with at least one other person to commit a crime, and an act in furtherance of that crime.  The only statutory defense to conspiracy is that no crime would have occurred if the conspiracy were carried out.

Wharton’s Rule

Although conspiracy is codified by statute, its application is further defined by case law.  One such limitation is Wharton’s Rule, becoming law when the U.S. Supreme Court applied it in Iannelli v. United States.  Wharton’s Rule is that a conspiracy cannot be found if the offense naturally requires two people for it to be committed.  For example, the crime of bigamy, gambling, and dealing in contraband require two people to be involved before its even a crime so the law cannot further punish the participants by charging them with conspiracy.

The application of this rule, which seems simple enough, is further complicated when applied to criminal drug conspiracies.  Since drug deals are typically those type of offenses that require two people to be a crime, some offenders have attempted to argue that they cannot be guilty of conspiracy under Wharton’s Rule.  This argument has failed by limiting the rule to apply to those crimes that do not impact society at large and presumed only when there is no legislative intent to the contrary in that jurisdiction.  See People v. Melgoza.  In practice, however, defendant’s have been able to successfully argue the absence of a conspiracy unless the State can prove that an actual agreement existed to distribute drugs, rather than just a buyer-seller arrangement.  See People v. Stroud.


Under the conspiracy statute, an offender found guilty of conspiracy can be sentenced according to the underlying crime that he was intending to commit.  This means that you can serve serious time for a crime that wasn’t even perpetrated.  The rationale for such severe punishment is inline with the old saying, “two heads are better than one.”  Criminal enterprises that utilize teamwork are that much more dangerous than criminals who act alone.

Given the potential punishment and complex nature of the law, if you are accused of a conspiracy, seek the immediate advice of a qualified Illinois Criminal Defense Attorney.

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