"A conspiracy is rarely, if ever, proved by positive testimony. When a crime of high magnitude is about to be perpetrated by a combination of individuals, they do not act openly, but covertly and secretly. The purpose formed is known only to those who enter into it. Unless one of the original conspirators betray his companions and give evidence against them, their guilt can be proved only by circumstantial evidence...and circumstances can not lie." - Special Judge Advocate John A. Bingham, The Trial Of The [Catholic] Conspirators, Lincoln Assassination, Washington, D.C., 1865