fighters; nor the management and safe disposition of escaped black slaves — who were not to be repatriated to the Confederacy, per the Act Prohibiting the Return of Slaves (13 March 1862). To resolve the lack of military authority in the 1806 Articles of War, Commanding General of the Union Army Halleck commissioned Prof. Lieber to write military laws specific to the modern warfare of the American Civil War. For the Union Army's management and disposal of irregular fighters (guerrillas, spies, saboteurs, et al.), Lieber wrote the tract of military law Guerilla Parties Considered with Reference to the Laws and Usages of War (1862), which disallowed a soldier’s POW-status to Confederate guerrillas and irregular fighters with three functional disqualifications: (i) guerrillas do not wear the army uniform of a belligerent party to the war; (ii) guerrillas have no formal chain of command, like a regular army unit; and (iii) guerrillas cannot take prisoners, as could an army unit. At the end of 1862, Gen. Halleck and War Secretary Stanton commissioned Lieber to revise the military law of the 1806 Articles of War to include the practical considerations of military necessity and the humanitarian needs of civilian populations under military occupation. The editorial-revision committee, Maj. Gen. Ethan A. Hitchcock and Maj. Gen. George Cadwalader, Maj. Gen. George L. Hartsuff and Brig. Gen. John Henry Martindale, requested from Lieber comprehensive military laws to govern the Union Army’s prosecution of the civil war. Gen. Halleck edited Lieber’s military law to concur with the Emancipation Proclamation (1 January 1863), and, on 24 April 1863, President Lincoln promulgated General Orders No. 100, Instructions for the Government of the Armies of the United States in the Field, the Lieber Code (1863). Legal provisions For the Union Army’s prosecution of the American Civil War, General Orders No. 100 (24 April 1863) concern the practical particulars of martial law, military jurisdiction, and the treatment of Confederate irregular fighters, such as spies, deserters, and prisoners of war. In the field practice of military justice, the unit commander held authority for any prosecution under the Lieber Code, which command authority included the summary execution of Confederate prisoners of war and war-criminal soldiers of the Union Army. In the context of the American Civil War, the Lieber Code explains the concepts of military necessity and humanitarian needs in articles 14, 15, and 16 of Section I: In the late 19th century,