Wis. Stat. § 939.31
Except as provided in ss. 940.43(4), 940.45(4) and 961.41(1x), whoever, with intent that a crime be committed, agrees or combines with another for the purpose of committing that crime may, if one or more of the parties to the conspiracy does an act to effect its object, be fined or imprisoned or both not to exceed the maximum provided for the completed crime; except that for a conspiracy to commit a crime for which the penalty is life imprisonment, the actor is guilty of a Class B felony.
Wis. Stat. § 939.31
A conspiracy may be unilateral; a person can enter into a conspiracy to accomplish a criminal objective in which only the defendant has a criminal intent. State v. Sample, 215 Wis. 2d 487, 573 N.W.2d 187 (1998), 96-2184. When the object of a conspiracy is the commission of multiple crimes, separate charges and convictions for each intended crime are permissible. State v. Jackson, 2004 WI App 190, 276 Wis. 2d 697, 688 N.W.2d 688, 03-2066. There is a distinction between conspiracy as a substantive inchoate crime under s. 939.31 and conspiracy as a theory of prosecution for a substantive crime under s. 939.05(2) (c). State v. Jackson, 2005 WI App 104, 281 Wis. 2d 137; 701 N.W.2d 42, 04-1603. The agreement to commit a crime that is necessary for a conspiracy may be demonstrated by circumstantial evidence and need not be express; a tacit understanding of a shared goal is sufficient. The intent to commit the crime may be inferred from the person's conduct. A stake in the venture is not a necessary element of the crime although evidence of a stake in the venture may be persuasive of the degree of the party's involvement in the crime. State v. Routon, 2007 WI App 178, 304 Wis. 2d 480, 736 N.W.2d 530, 06-2557. A person may be a member of a conspiracy in particular, a conspiracy to manufacture a controlled substance based on the person's sale of goods that are not illegal to sell or possess. One does not become a party to a conspiracy by aiding and abetting it, through sales of supplies or otherwise, unless he or she knows of the conspiracy, the inference of which knowledge cannot be drawn from mere knowledge that the buyer will use the goods illegally. The gist of the conspiracy is the seller's intent, when given effect by an overt act to further, promote, and cooperate in the buyer's intended illegal use. There must be clear, unequivocal evidence of the seller's knowledge of the buyer's intended illegal use. State v. Routon, 2007 WI App 178, 304 Wis. 2d 480, 736 N.W.2d 530, 06-2557. Under a unilateral conspiracy, a person who intends to accomplish the objects of the conspiracy is guilty even though the other members of the conspiracy never intended that a crime be committed. This same logic applies to the next step: that is, when the fulfillment of the conspiracy is not only highly unlikely, but is legally impossible. State v. Huff, 2009 WI App 92, 319 Wis. 2d 258, 769 N.W.2d 154, 08-2664. For an act to performed by one of the conspirators in furtherance of the conspiracy, an overt act must be done toward the commission of the intended crime that must go beyond mere planning and agreement. However, the act need not, by itself, be an unlawful act or an attempt to commit the crime. If there was an act that was a step toward accomplishing the criminal objective, that is sufficient. In this case, the defendant's act of communicating to a detective that cocaine was available for immediate delivery was such an overt act. State v. Peralta, 2011 WI App 81, 334 Wis. 2d 159, 800 N.W.2d 512, 10-0563.