That hereafter all persons found within our lines who commit acts for the benefit of the enemies of our country, will be tried as spies or traitors, and, if convicted, will suffer death. This order includes the following classes of persons:
The habit of declaring sympathies for the enemy will no longer be tolerated in the department. Persons committing such offences will be at once arrested, with a view to being tried as above stated, or sent beyond our lines into the lines of their friends.
Any kind of opposition to the war — such as that expressed by the Copperheads peace movement — was considered sympathy to the enemy, and the order was immediately used as justification to arrest Ohio senator Clement Vallandigham, a prominent leader in the movement (in fact, he was arrested for criticizing the order itself), and to try him in a military court.