Conspiracy is distinct from the substantive crime contemplated by the conspiracy and is charged as a separate offense. Conspiracy is one of the most commonly charged Federal crimes and is applied in varied situations. The four elements of a criminal conspiracy are that: (1) an agreement exists between at least two parties; (2) they agree to achieve an illegal goal; (3) they have knowledge of the conspiracy and participate in the conspiracy; and (4) at least one conspirator commits an overt act in furtherance of the conspiracy. Defendants can challenge conspiracy charges by claiming a failure to prove the specific elements of the offense or by contesting the charge on more general grounds, including the statute of limitations, insufficiency of indictment, variance, multiplicitous indictment, insufficient evidence, and withdrawal. Most conspiracy trials necessarily include testimony by co-conspirators and thus involve the co-conspirator exception to the hearsay rule. Consecutive sentences can be imposed for convictions conspiracy and the substantive offense. The Federal Sentencing Guidelines provide specific rules governing the sentencing ranges for conspiracies to commit particular offenses. Footnotes