Lieber Code

The Lieber Code of April 24, 1863, also known as Instructions for the Government of Armies of the United States in the Field, General Order № 100, or Lieber Instructions, was an instruction signed by US President Abraham Lincoln to the Union Forces of the United States during the American Civil War that dictated how soldiers should conduct themselves in wartime. Its name reflects its author, the German-American legal scholar and political philosopher Franz Lieber.

Lieber had fought for Prussia in the Napoleonic Wars and had been wounded at the Battle of Waterloo. He had lived and taught for two decades in South Carolina, where he was exposed to the horrors of slavery. Beginning in October 1861, as professor of history and political science at what became Columbia University, Lieber delivered a series of lectures at the new Law School entitled "The Laws and Usages of War". He believed the methods used in war needed to align with the goals and that the ends must justify the means, and he published the lectures as "International Law, or, Rules Regulating the Intercourse of States in Peace and War".

During the American Civil War, soldiers were faced with a number of ethical dilemmas. Lieber knew about some from his own European wartime experiences, as well as through his sons (two of whom fought for the Union, and another died fighting for the Confederacy near Williamsburg). While in St. Louis searching for one of his sons, who had been wounded at Fort Donelson, Lieber met Union General Henry Halleck, who had been a lawyer in civilian life. As the war dragged on, the treatment of spies, guerrilla warriors, and civilian sympathizers became especially troublesome. So too was the treatment of escaped slaves, who were forbidden to return to their owners by an order of March 13, 1862. After Halleck became general-in-chief in July, 1862, he solicited Lieber's views. The professor responded with a report, "Guerilla Parties Considered With Reference to the Laws and Usages of War", and Halleck ordered 5000 copies printed. That same summer, Lieber advised Secretary of War Edwin Stanton concerning the "military use of colored persons".

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