The Lieber Code

by Burrus M. Carnahan

The Lieber Code and the law of war in the Civil War.

The Civil War produced one of the most significant American contributions to the development of international law in the nineteenth century, the “Lieber Code.” The Code, a concise handbook on the international law of war issued for the use of Union army officers, was one response by the United States government to a fundamental disagreement between the North and the South as to the nature of the war they were fighting.

The Confederate government, of course, rejected the very idea that it was fighting a civil war, and continually pressed the United States, as well as neutral governments, to accord the Confederacy all the international rights of a sovereign nation. On the other hand, the Lincoln administration and its supporters just as adamantly refused to recognize any legitimacy for the government in Richmond, arguing that, since secession from the Union was unconstitutional; the United States was fighting against a group of individual, but well-organized, rebels rather than a confederation of seceded states.

Nevertheless, within months of the fall of Fort Sumter the Lincoln administration slowly and reluctantly started to treat Confederate soldiers in accordance with the rights and privileges due to enemy personnel under international law. This process was well under way by July 14, 1861, when General Winfield Scott, commanding officer of the U.S. Army, ordered that Confederate soldiers captured in western Virginia be treated as prisoners of war under the “usages of war,” another term for the international law of war.[1] By the end of August 1861 the U.S. War Department was using a “flag of truce boat” to communicate with Confederate military officials at Norfolk, Virginia.[2] In October of that year the government appointed an officer as “Commissary of Prisoners,” to establish and run prisoner of war camps in the North.[3] These decisions appear to have been taken due to a combination of factors, including practical necessity, Confederate threats of retaliation, and domestic political pressure to ensure that captured Union soldiers were treated as prisoners of war by the Confederates.

At first there were a few issues on which the Lincoln administration wanted to maintain a firmer line. In his April 19, 1861, proclamation declaring a blockade on seaports in the rebellious states, President Abraham Lincoln had also announced that “if any person under the pretended authority of the said [Confederate] States, or under any other pretense, shall molest a vessel of the United States, or the persons or cargo on board of her, such persons will be held amenable to the laws of the United States for the prevention and punishment of piracy.” [4] In other words, if any Confederate officers or sailors attacked a Union merchant ship, they would not be treated as prisoners of war but instead tried--and presumably--hanged as pirates.

When a captured officer from a rebel privateer (a privately-owned warship licensed by the Confederate government to prey on Union shipping) was actually sentenced to death as a pirate,[5] the Confederate government, not surprisingly, threatened to hang a Union prisoner of war in retaliation if the sentence was carried out, and for that purpose a colonel of New York State Militia was placed on death row in the Virginia state penitentiary.[6] After almost three months of negotiations, the Lincoln administration capitulated and at the end of January, 1862, orders were given that naval and privateer prisoners were to be regarded as prisoners of war and turned over to the U.S. military.[7]

At about the same time the Lincoln administration reversed itself on another aspect of prisoner policy. In the nineteenth century, it was customary for armies at war to conclude an agreement, known as an exchange cartel, to facilitate regular exchanges of prisoners while the war was still going on. Great political pressure was placed on the Lincoln administration to negotiate such a cartel with the Confederate army.[8] Throughout 1861, Attorney General Edward Bates objected to negotiating an exchange cartel, believing it would grant increased recognition and legitimacy to the Confederate government.[9] However, after consulting with experts on international law, including Columbia University professor Dr. Francis Lieber, Bates and other administration officials concluded that the Union could enter into an exchange cartel on a purely humanitarian basis, without implied recognition of the Confederate government.[10] On February 11, 1862, Secretary of War Edwin M. Stanton directed Major General John Wool, commanding officer at Fort Monroe, Virginia, to begin cartel negotiations with his Confederate counterpart at Norfolk, Virginia, across Hampton Roads.[11]

By early 1862, then, the U.S. government was according Confederate officers, soldiers and sailors all the rights and privileges established by the international laws and usages of war. This gave rise to a new problem for the Lincoln administration – ensuring that U.S. Army officers knew what the laws and usages of war required. As early as July 1861, when the administration was still formulating its prisoner policies, U.S. Army Quartermaster General Montgomery Meigs warned the secretary of war that when handling prisoner of war issues, “[k]nowledge of military law and custom is needed in order not to offend by errors of ignorance in treating these delicate questions.” [12] The rapid expansion of the Union army during the war meant that the vast majority of officers had been appointed directly from civilian life, and had no knowledge of the laws and usages of war.[13]

By the time he was appointed commanding general of the U.S. Army in July 1862, Major General Henry Halleck was well aware of the need to provide practical guidance on the laws and usages of war to officers in the field. Even though he was himself an authority on international law, Halleck had faced a number of difficult problems, including ignorance on the part of his subordinates, when dealing with guerrilla warfare while he was in command of the Department of the Missouri. After assuming command of the entire U. S. Army, Halleck asked Professor Lieber for advice on how to distinguish legitimate enemy combatants, who were entitled to prisoner of war treatment, from unlawful guerillas who could be punished if captured. As a result, Lieber produced a pamphlet on Guerrilla Parties Considered with Reference to the Laws and Usages of War.[14] Halleck was delighted with the pamphlet, and ordered 5,000 copies to be printed at government expense for the guidance of army officers. In December 1862, General Halleck took the next step and had the War Department appoint Lieber and four generals to a board “to propose amendments or changes to the Articles of War, and a code of regulations for the government of armies in the field, as authorized by the laws and usages of war.”[15] The generals decided they would undertake review of the Articles of War, and left the codification of the laws and usages of war to Dr. Lieber.

Though a Prussian by birth, Francis Lieber (1798 – 1872) was uniquely qualified to write a summary of the international laws and usages of war for use during the American Civil War. Having served as a soldier in the Prussian army, he was a combat veteran who had been severely wounded in the final battles of the Napoleonic Wars. After earning a doctorate from the University of Jena, in the 1820s he volunteered to fight in the Greek war of independence from Turkey. Returning from Greece, he was persecuted by the Prussian police due to his democratic political beliefs and fled to Boston in 1827. Unable to find a permanent academic position in New England, in 1835 he accepted a position as professor of political economy at a college in South Carolina in spite of his personal opposition to slavery. He returned to the North in 1855 and was eventually appointed professor of political science at Columbia College (soon renamed Columbia University) in New York City.

The outbreak of the Civil War divided Lieber’s family. His oldest son, who had remained in South Carolina, died while fighting for the Confederacy. His other two sons joined the Union army and one was severely wounded. The laws and usages of war were more than merely academic concepts to Francis Lieber. [16]

Dr. Lieber was also uniquely qualified by the research resources available to him. During his years in South Carolina he had accumulated massive files documenting international military and diplomatic practices in Europe and the Americas. From these he was able to deduce patterns in international behavior that allowed him to test whether the rules and principles stated by earlier writers on international law were reflected in the actual practice of countries at war.[17]

Drawing on these resources, by the end of February 1863 Lieber produced the first draft of a short guide to the laws and usages of war for review by the other members of the War Department board.[18] After a few minor changes, Lieber’s draft was signed by President Lincoln as commander-in-chief and issued by the War Department as General Orders No. 100, with an official date of April 24, 1863.[19] Although issued as an official U.S Army document, it is commonly referred to as the Lieber Code.

Consisting of 157 articles, the Lieber Code was a concise summary, in plain language, of the laws and usages of land warfare as they had developed up to the middle of the nineteenth century. The Code covered almost all legal issues an army officer was likely to encounter in the field, including treatment of prisoners of war, the punishment of spies and guerillas, proper use of the white flag of truce, the conclusion of temporary cease-fire agreements with the enemy, and the treatment of enemy civilians and civilian property in occupied territory. By way of comparison, the 1949 Geneva Convention on Prisoners of War (currently in force) is 143 articles long, plus five annexes, and covers only some of the issues the Lieber Code dealt with.

One of Lieber’s most significant achievements was clarifying the legal concept of “military necessity.” While earlier books on international law had vaguely called for only the use of “necessary” force in war,[20] the Lieber Code gave the following detailed guidance on what this legal principle did and did not permit:

Art. 14. Military necessity, as understood by modern civilized nations, consists in the necessity of those measures which are indispensable for securing the ends of the war, and which are lawful according to the modern law and usages of war.

Art. 15. Military necessity admits of all direct destruction of life or limb of armed enemies, and of other persons whose destruction is incidentally unavoidable in the armed contests of the war; it allows of the capturing of every armed enemy, and every enemy of importance to the hostile government, or of peculiar danger to the captor; it allows of all destruction of property, and obstruction of the ways and channels of traffic, travel, or communication, and of all withholding of sustenance or means of life from the enemy; of the appropriation of whatever an enemy's country affords necessary for the subsistence and safety of the army, and of such deception as does not involve the breaking of good faith either positively pledged, regarding agreements entered into during the war, or supposed by the modern law of war to exist. Men who take up arms against one another in public war do not cease on this account to be moral beings, responsible to one another and to God.

Art. 16. Military necessity does not admit of cruelty - that is, the infliction of suffering for the sake of suffering or for revenge, nor of maiming or wounding except in fight, nor of torture to extort confessions.

It does not admit of the use of poison in any way, nor of the wanton devastation of a district. It admits of deception, but disclaims acts of perfidy; and, in general, military necessity does not include any act of hostility which makes the return to peace unnecessarily difficult.

Confederate authorities were particularly critical of Lieber’s principle of military necessity. Shortly after the Lieber Code was issued, Confederate Secretary of War James Seddon complained to a subordinate that the concept was so flexible that “a military commander under this code may pursue a line of conduct in accordance with principles of justice, faith, and honor, or he may justify conduct correspondent with the warfare of the barbarous hordes who overran the Roman Empire ….”[21] There was some truth in this criticism, particularly in relation to the treatment of private property later in the war by General William T. Sherman in Georgia and the Carolinas (1864-65) and General Phillip Sheridan in the Shenandoah Valley of Virginia (1864).

Seddon failed to note, however, Lieber’s warning that military necessity only justified acts “which are lawful according to the modern law and usages of war.” Military necessity would not permit acts in violation of a specific rule of that law, such as the prohibition on use of poison or abuse of a flag of truce (for example, launching a surprise attack after the enemy ceased firing in response to the raising of a white flag). War crimes tribunals in the twentieth and twenty-first centuries have generally agreed with Lieber’s position and have rejected “military necessity” as a defense for violations of specific rules of the law of war.

Another important, and lasting, contribution of the Lieber Code to international law was its declaration that the law of war did not allow racial discrimination. By 1863, the Union army was recruiting units of African-American soldiers. Confederate officials claimed the use of such troops was intended to provoke a bloody slave rebellion (a “servile war”) in the South, and treated captured African-American soldiers as escaped slaves rather than prisoners of war.[22] In response, the Lieber Code asserted that the “law of nations knows of no distinction of color” (article 58) and that “[n]o belligerent has a right to declare that enemies of a certain class, color, or condition, when properly organized as soldiers, will not be treated” as prisoners of war (article 57). This condemnation of racial discrimination, at a time when it was lawful and even required in many states, laid the foundation for one of the most important principles of international human rights law as it developed in the late twentieth century.

The Lieber Code remained the standard guidance on the law of war for the U. S. Army until a new manual was issued in 1914, and even that extensively quoted from the Code.[23] The Lieber Code had even more influence at the international level. Up until the mid-nineteenth century, the law of war developed gradually through the general acceptance of international custom by various countries. From that time on, however, it has developed principally through the negotiation of treaties (sometimes also called “conventions” or “declarations”) that were signed and ratified by a large number of nations. Early examples include the initial Geneva Convention of 1864, that established the Red Cross as an international symbol for military hospitals and medical personnel,[24] and the 1868 Saint Petersburg Declaration that outlawed use of explosive rifle bullets in war.[25]

The first successful effort to bring together all the rules of land warfare in a single treaty came at the 1899 Peace Conference held at The Hague, Netherlands. The Hague Conference adopted a set of Regulations on Land Warfare that were directly adapted from the Lieber Code ,[26] The Hague Regulations have been revised and updated by periodic negotiations since then, most recently in a 1977 Protocol to the Geneva Conventions.[27] Through its influence on international negotiations up to the present day, the Lieber Code truly became, as Dr. Lieber had predicted, “a contribution by the U.S. to the stock of common civilization.”[28]

  • [1]General Scott to General George B. McClellan, July 14, 1861, in War of the Rebellion: Official Records of the Union and Confederate Armies .U.S. Gov’t Printing Office, 1880-1901, series 2, vol. 3, at 10-11 (Hereinafter cited as OR).
  • [2] General John A. Dix to General John E.Wool, August 22, 1861, OR, series 2, vol. 3, at 27-28.
  • [3] War Department, Special Order #284, Washington, October 23, 1861, OR, series 2, vol. 3, at 121.
  • [4] Proclamation of a Blockade, April 19, 1861, 4 Collected Works of Abraham Lincoln 338-39 (Roy Basler ed., 1953).
  • [5] See United States v. William Smith, October 22, 1861 (U.S. District Court for the Eastern District of Pa.), in OR, series 2, vol. 3, at 58-69.
  • [6] See Colonel Milton Cogswell to General Lorenzo Thomas, November 11, 1861, in OR series 2, vol. 3, at 130-31.
  • [7] See William H. Seward to U.S. Marshals, January 31, 1862, in OR series 2, vol. 3 at 229; General Wool to General Benjamin Huger, February 10, 1862, id.  at 250.
  • [8] See, e.g., Governor William Sprague (RI) to Lincoln, October 3, 1861; Governor John A. Andrew (Mass.) to Lincoln, Nov. 25, 1861, both in Abraham Lincoln Papers , Library of Congress, online edition <>.  On December 11, 1861, the House of Representatives passed a resolution requesting the President “to inaugurate systematic measures for the exchange of prisoners in the present rebellion,” in OR series w, vol. 3, at 157.
  • [9] At a cabinet meeting on December 10, 1861, for example, Bates opposed the negotiation of a general cartel for the exchange of prisoners of war, believing this would accord further recognition to the Confederacy.  See Inside Lincoln’s Cabinet, The Civil War Diaries of Salmon P. Chase 49 (David Herbert Donald ed., 1954).
  • [10] See Frank Freidel, Francis Lieber, Nineteenth Century Liberal  307-09, 313-14, 320 (1968 reprint of 1947 ed.).
  • [11] See Stanton to General Wool, February 11, 1862, in OR series 2, vol. 3, at 254.  These negotiations eventually resulted in the conclusion of the Dix-Hill Cartel on July 22, 1862, see OR series 2, vol. 4, at 266.
  • [12] Montgomery Meigs to Simon Cameron, July 12, 1861, in OR, series 2, vol. 3, at 8.
  • [13] At the beginning of 1861, there were approximately 16,000 officers and men in the U.S. Army.  By the end of 1864, the army consisted of almost a million officers and men. See David J. Eicher, The Longest Night: A Military History of the Civil War , 58, 785 (2001).
  • [14] Francis Lieber, Guerrilla Parties Considered with Reference to the Laws and Usages of War in Richard Shelly Hartigan, Lieber’s Code and the Law of War 31-44 (1983).
  • [15] Paragraph 5, Special Orders No. 399, War Department, Adjutant General’s Office, Washington D.C., December 17, 1862, in OR, series 3, vol. 2, at 951.
  • [16] See generally Frank Freidel, supra note 10.
  • [17] See Frank Freidel, supra note 10, at 37-38; 147-48.
  • [18] See id. at 331-34.
  • [19] Instructions for the Government of Armies of the United States in the Field, General Orders No. 100, War Department, Adjutant General’s Office, Washington D.C., April 24, 1863, in OR, series 3, vol. 3, at 148-64.
  • [20] See, e.g., Henry Wheaton, Elements of International Law with a Sketch of the History of Science, 249-51 (2002 reprint of 1836 ed.).  Henry Wheaton was the first American to write extensively on international law.
  • [21] Seddon to General Robert Ould, June 24, 1863, in OR series 2, vol. 6, at 41.
  • [22] See Confederate States Army, General Order 111, December 23, 1862 in OR, series 1, vol. 15, at 906; cf. Seddon to General Ould, June 24, 1863, supra note 21 at 45.
  • [23] U.S. War Department, Office of the Chief of Staff, Rules of Land Warfare, (War Department Document No. 467, issued April 25, 1914).
  • [24] Convention for the Amelioration of the Condition of the Wounded in Armies in the Field, August 22, 1864, in The Laws of Armed Conflicts:  A Collection of Conventions, Resolutions and Other Documents 213-16 (Dietrich Schindler and Jiri Toman, eds., 1981).
  • [25] Declaration Renouncing the Use, in Time of War, of Explosive Projectiles Under 400 Grammes Weight, November 29/December11, 1868, in The Laws of Armed Conflicts, supra, at 95-97.
  • [26] Regulations Annexed to Convention (II) with Respect to the Laws and Customs of War on Land, July 29 1899, in The Laws of Armed Conflicts, supra at 57-92.
  • [27] Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts (Protocol I), June 8, 1977, in The Laws of Armed Conflicts, supra, at 551-618.
  • [28] Lieber to General Halleck, May 20, 1863, in Richard Shelly Hartigan, supra note 14, at 120.  Spelling as in original.

If you can read only one book:

Richard Shelly Hartigan, Lieber’s Code and the Law of War. Chicago: Precedent Publishing, 1983.


  • Frank Freidel, Francis Lieber, Nineteenth Century Liberal. Baton Rouge LA: Louisiana State University, 1947.

  • Theodor Meron, War Crimes Law Comes of Age: Essays, Ch.5. Oxford: Clarendon Press, 1998.

  • Stephen C. Neff, Justice in Blue and Gray: A Legal History of the Civil War, Ch.3-4. Cambridge: Harvard University Press, 2010.

  • Joshua E. Kastenberg, Law in War, War as Law: Brigadier General Joseph Holt and the Judge Advocate General’s Department in the Civil War and Early Reconstruction 1861-1865, Ch.8-9. Durham NC: Carolina Academic Press, 2011.

  • Burrus M. Carnahan, Act of Justice: Lincoln’s Emancipation Proclamation and the Law of War, Ch.7-8. Lexington: University Press of Kentucky, 2007.

  • Burrus M. Carnahan, Lincoln on Trial: Southern Civilians and Law of War. Lexington: University Press of Kentucky, 2010.


  • The Lieber Society on the Law of Armed Conflict.

    The Lieber Society is an Interest Group open to members of the American Society of International Law. For more information consult the Society’s

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Web Resources:

  • The web site of the International Committee of the Red Cross International has the full text, with brief historical commentary, of the Lieber Code and the treaties and proposed treaties that were developed from it in the 19th and 20th centuries. In the search box type Lieber Code to see all 157 articles of the Code.

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Other Sources:

  • The Francis Lieber Papers.

    The papers of Francis Lieber are held by the Huntington Library in San Marino, California. For information on access consult the Library’s web site

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