A third inchoate offense, next to attempt and solicitation, is conspiracy. Because conspiracy law is complex, we'll tackle it in two parts, beginning here by looking at the common law's approach.

I. Agreement

The essence of conspiracy is an agreement between two or more people to commit unlawful activity. Like solicitation, a person can be charged with conspiracy even though his or her conduct occurs long before the crime is actually committed.

Traditionally, conspiracy, like the other...