General Orders No. 100: Instructions for the Government of Armies of the United States in the Field Summary

  • Last updated on November 10, 2022

General Orders No. 100 was a military order that instructed US army soldiers on the expected conduct during wartime. Dubbed the Lieber Code, the order was drafted by Francis Lieber and, upon approval by a group of senior Union Army officers, was promulgated to the military on behalf of President Abraham Lincoln. This set of orders prohibited the willful destruction of property, torture, and other forms of cruelty toward the enemy. It also called for soldiers to be respectful of noncombatants and unarmed captives and prohibited intentionally killing any prisoners of war. The Lieber Code, in essence, aimed to remove the aspects of revenge, cruelty, and savagery that often accompany war. These orders have since been adapted in other countries and remain highly relevant in the modern era.

Summary Overview

General Orders No. 100 was a military order that instructed US army soldiers on the expected conduct during wartime. Dubbed the Lieber Code, the order was drafted by Francis Lieber and, upon approval by a group of senior Union Army officers, was promulgated to the military on behalf of President Abraham Lincoln. This set of orders prohibited the willful destruction of property, torture, and other forms of cruelty toward the enemy. It also called for soldiers to be respectful of noncombatants and unarmed captives and prohibited intentionally killing any prisoners of war. The Lieber Code, in essence, aimed to remove the aspects of revenge, cruelty, and savagery that often accompany war. These orders have since been adapted in other countries and remain highly relevant in the modern era.

Defining Moment

In the summer of 1862, the Union Army was in a state of confusion after it failed to break the back of the Confederacy by capturing its capitol in Richmond, Virginia. General George McClellan, leader of the Army of the Potomac, had shown considerable restraint in dealing with the Confederates in that region, as the rebels were using guerilla tactics, such as not wearing uniforms and blending into the landscape and launching attacks from within civilian structures. McClellan’s wariness of attacking the enemy without restraint sent the army into retreat as the Confederates continued to push northward.

Frustrated by this defeat, President Abraham Lincoln met with McClellan soon after the Richmond defeat. Although he would be soon relieved of his command, McClellan successfully argued to Lincoln that there should be standards for the civil conduct of wartime operations. This war, McClellan insisted, should not be about subjugating the people of the South, but about defeating the Confederate States Army and the political machines that supported it. Therefore, he argued, the Union was in need of a formal set of rules that prevented, wherever possible, the brutality and cruelty that was common in times of war.

Lincoln agreed with McClellan and looked to his general-in-chief of the army, Henry Halleck, to develop a set of standards according to which the Union Army should conduct itself when dealing with insurgents like those operating alongside the formal Confederate Army. Halleck, finding no such guidelines in the Union Army’s codes, turned to an expert on the conduct of war: Professor Francis Lieber of Columbia College (now Columbia University). Lieber had lost one son who fought for the Confederate side and was killed during the Battle of Williamsburg in 1862. His two other sons were fighting with the Union Army.

Lieber’s response to Halleck’s request was a comprehensive code of conduct for war, which prohibited such things as willful destruction of property and wanton acts of cruelty toward the enemy, civilians, and prisoners. However, Lieber, who was also a staunch advocate for the Union, provided exemptions that would allow for Lincoln’s army to be aggressive against a frequently deceptive and vexing Confederate enemy. Still, Lieber’s code of conduct provided an important set of rules for the Union to conduct military operations and adhere to the ethical treatment of the enemy and civilians in occupied areas.

The Lieber Code was quickly delivered to a council of senior Union military officers for approval. Upon acceptance, Lieber’s standards were quickly disseminated throughout the Union leadership for incorporation into their ongoing campaign against the Confederacy. The standards, now known as “General Orders Number 100: Instructions for the Government of Armies of the United States in the Field,” would serve as the basis for standards of wartime conduct adopted by other international organizations and countries throughout the twentieth century.

Author Biography

Francis Lieber (originally Franz Lieber) was born on March 18, 1798 or 1800, in Berlin, Germany. His father, Friedrich Wilhelm Lieber, was a successful ironworker. Lieber grew up during the Napoleonic Wars and experienced the French occupation of Berlin. His older brother joined the resistance against Napoleon’s expansion, while Franz developed an intense disdain for tyranny and a strong passion for liberty and patriotism. At the age of fourteen, he enlisted in the resistance cause and joined the Prussian Army’s Colberg Regiment in 1815. He was severely injured at the Battle of Waterloo, however, and returned home to Berlin.

After he recovered from his injuries, Lieber continued his education by studying under the mentorship of the liberal German thinker Friedrich Ludwig Jahn (who was an advocate for German patriotism). The Prussian government, seeking to stamp out any nationalistic fervor among its citizens, targeted Jahn and his young student. Confiscating a number of liberty-oriented songs that Lieber had composed, the authorities arrested Lieber and held him without trial for four months. When he was released, he was prohibited from enrolling in any university except the liberal University of Jena. He completed his doctorate at that university in 1820, and although he continued to study the concepts of liberty and nationalism, he was under strict control by the government. When this oppression became too much for Lieber, he traveled to Greece and Rome, occasionally being arrested for protesting the Prussian government’s heavy-handed control over its subjects.

Lieber eventually left his home in Berlin for London, where he was able to teach and write. After a year in London, Lieber was invited to oversee Harvard College’s gymnasium and evening school in 1827. Working with a number of prominent academics, he also founded and edited the thirteen-volume Encyclopaedia Americana from 1829 through 1833. Six years later, he married Mathilda Oppenheimer, whom he met while in London. The two spent the next two decades at South Carolina College (now the University of South Carolina), where Lieber wrote some of the first works in the developing field of political science in the United States, focusing on the role of the state and the people’s activity in democratic government.

In 1857, Lieber accepted a position as a professor at New York’s Columbia College. One of the first critics of the notion of Southern secession, Lieber became known for both his pro-Union writings and his knowledge of military law. Lieber, a staunch supporter of the Union, became personally involved in the war, as one of his sons enlisted in the Confederate Army and his other two sons joined the Union. Lieber assisted the War Department, compiling and writing a wide range of pamphlets for distribution in the army.

After the war, Lieber stayed with Columbia’s law school. He was also charged with analyzing captured Confederate documents, looking for evidence of treason and other crimes. Furthermore, he worked for two years as a negotiator with the Mexican Claims Commission, and he later helped to found the American Social Science Association. Lieber was working on a project to codify international law before he died on October 2, 1872.

Document Analysis

The Lieber Code is a comprehensive document, covering a wide range of issues that may arise during periods of war and conflict. It is broken into ten separate sections, each of which addresses certain themes, such as the protection of noncombatants and their property, treatment of partisans (armed parties who do not belong to an established army but fight in support of the enemy), prisoners of war, and even assassinations. In total, General Orders No. 100 contained 157 provisions that were to be promulgated and adopted by the members of the Union Army.

The first section focuses on the application of martial law, military jurisdiction, military necessity, and retaliation. Article 15, for example, acknowledges that destruction, casualties and injuries, and the taking of prisoners are inevitabilities in war. However, the article also says that war does not excuse humans from the responsibility to act in a morally upright fashion–humanity, according to the article, must continue to be responsible to one another as well as to God. Although war necessitates violence and often the destruction and seizure of property, Lieber states that combatants should still remain true and uphold all good-faith agreements entered into with the enemy.

Article 16 of this section distinguishes military action from wanton acts of cruelty and destruction. Lieber acknowledges that military necessity results in violence and destruction. However, military necessity does not allow for “the infliction of suffering for the sake of suffering or for revenge.” The act of torture or other forms of cruelty, according to the orders, is unacceptable. Then again, Lieber says, there are instances in which deception is a part of military strategy. Still, he adds, there is no place for acts of perfidy (disloyalty or treason).

Military actions, according to the orders, do not always use guns or cannon as weapons. In some cases, an enemy may be surrounded and with his supply lines cut. Such sieges did take place during the Civil War. During the Battle of Vicksburg (1863) in Mississippi, for example, the Union held a strong position on the hilltops above the city, cutting off the supply lines. The soldiers simply waited for the Confederates to surrender when their supplies were exhausted. According to Articles 17 and 18, siege tactics are lawful and even useful for hastening the surrender of the enemy.

The next few articles of the first section of General Orders No. 100 point out that in war, there are official military personnel who act on behalf of a belligerent nation. Article 20 explains that public war is “a state of armed hostility between sovereign nations or governments,” and people naturally form organized units such as states or nations. By allowing themselves to be subject to the laws and authority of the political institutions under which they live, citizens of a belligerent nation may be considered enemies, even if they do not take up arms against opposing military forces.

In light of this, the Union Army would be well-advised, the instructions state, to be mindful of the presence of civilians on the battlefield. Commanders, according to Article 19, are encouraged to notify the civilian residents of an enemy stronghold before bombardment occurs. Still, as bombing attacks may warrant the element of surprise, a lack of notification would not be considered unlawful or unethical. The important point being made is that civilian noncombatants frequently live among the members of an enemy military force. If at all possible, the Union Army should make an effort to spare the lives and property of unarmed citizens. However, the safety of civilian noncombatants who live among the military representatives of their nation cannot always be guaranteed.

Giving No Quarter

Mercy is a theme that permeates these general orders. A discussion is included, therefore, of the concept of giving no quarter. The phrase “give no quarter” means to show an enemy no mercy or compassion; it is thought to derive from the idea not quartering, or housing, enemy soldiers, meaning they will not be taken prisoner and must instead be killed. The Lieber Code acknowledges that such a practice may exist under certain limited circumstances in wartime, and it provides some guidance on what those circumstances are. Article 60 of Section III prohibits a body of troops from taking it upon themselves to give no quarter, although a commander may give such an order when his unit’s survival depends upon taking no prisoners, as when detaining or transporting them presents a danger to the Union troops (such as through the exhaustion of supplies). Furthermore, according to Article 61, it is not acceptable to give no quarter to disabled or wounded troops or to enemy combatants taken prisoner by other military units.

Several other circumstances may occur when giving no quarter is acceptable. According to Section III, Article 62, for example, if the enemy issues the order to give no quarter to Union troops, it should expect no quarter in return. Additionally, Article 63 explains that an enemy combatant who launches a deceitful attack while wearing a Union uniform may expect no mercy as well. Also, under Article 66, if an enemy gives no quarter while American forces show mercy, and a member of the enemy’s forces is captured, that individual may expect no quarter in light of his association.

General Orders No. 100 place great value on the uniforms and flags borne by the warring parties into battle. According to Articles 63 and 64 of the code, for example, if a Union force acquires a supply of enemy uniforms and is in need of distributing them to their own troops, the soldiers must place some sort of highly visible mark on their uniforms so that they may be distinguished from the enemy. Should these troops fail to do so, they may expect no quarter from the enemy. Furthermore, as stated in Article 65, a combatant that uses the enemy’s flag or other national emblem to deceive their opponents would again be committing an act of perfidy. As a result, that force would lose “all claim to the protection of the laws of war.”

Section III also makes a statement about the general law of warfare that applies to all nations. Article 67, for example, states that nations have the right to declare war on one another, but those countries should not presume that the rules of warfare do not apply to them. Even if a captor believes the enemy to be unjust, that captor must still abide by the rules of proper treatment of prisoners.

In general, a state of war should not exist without purpose. In other words, nations should not wage war on others simply for the sake of killing an enemy. War should have a discernible objective other than revenge or the willful destruction of the enemy. Several articles in Section III speak to this rule. Article 70, for example, strictly prohibits the use of poison (such as poisoning a water or food supply). Article 71 prohibits the army from deliberately injuring an enemy who is already wounded to the point of being disabled. Any combatant, whether Union or Confederate, who is found guilty of this crime would be subject to the death penalty. Furthermore, outposts and advanced outposts (pickets), because of their limited strengths, should be addressed with limited force under Article 69, and therefore, the army must issue a special order before engaging these outposts.

Treatment of Prisoners

The orders also address the seizure of an enemy prisoner’s belongings. Out of respect for the prisoner, any reasonable items belonging to a prisoner–such as jewelry, clothing, and money–shall be considered private property. It would be dishonorable for any member of the Union Army to take it or sell it. However, a prisoner found with large sums of money or goods may, after a reasonable amount is returned for the purpose of basic support, lose the surplus to the army. Such a decision must, however, be an official act sanctioned by an order of the commanding officer or the government itself.

The orders stipulate that a prisoner of war is a person worthy of dignity and respect. After all, under the ideals set forth in Section III, such people are the prisoners of the United States and not of the keepers of the detention facility. The government determines the terms by which a prisoner is detained. No prison official may therefore seek any sort of compensation or ransom from prisoners or their supporters (a provision of Article 74). Likewise, any attempt by a prisoner to pay his or her American captors for release would be fruitless.

Under the language of Article 73, a prisoner of the Union Army would be required to surrender his sidearm when detained. This weapon must then be carefully marked and stored. Such an action would demonstrate the respect the captor has for his prisoner and that individual’s bravery and honor as a soldier. It would also serve as a sign of the humane treatment the prisoner would receive while incarcerated.

It is to be expected that the quality of a prison and the treatment prisoners receive therein varies, Article 75 states. The resources available and concerns over the facility’s safety would dictate these variations. Prison guards and officials are expressly prohibited from deliberately subjecting prisoners to any form of indignity or suffering. The prisoners should be fed simple yet “wholesome” food and treated with dignity while within the prison’s walls. Additionally, any prisoner who was wounded in battle before capture, according to Article 79, must be treated to the best of the ability of the prison’s medical staff. Furthermore, the individuals held in a US government prison could be required to work in a manner befitting their physical capabilities and rank, a measure that is outlined in Article 76.

Section III further defines the government’s official policy toward prisoners of war by establishing rules governing escapes from prison camps and facilities. Article 77 says that a prisoner who has escaped the camp may be shot or otherwise killed. Interestingly, however, an escape attempt by a single prisoner shall not be considered a capital offense. In fact, it should not even be considered unlawful. Therefore, potential fugitives would not be subject to punishment if they are unsuccessful in their attempt. Instead, the prison would simply take account of the individual’s plan and bolster security in an appropriate manner.

Still, Article 77 makes another clear definition: groups of prisoners working collectively to stage a large-scale escape are subject to punishment. Such individuals would be considered part of a conspiracy and, therefore, may be “rigorously punished.” Furthermore, prisoners who take part in such conspiracies–such as those who plot a full rebellion against their captors–could be considered subject to the death penalty. There are also rules governing an individual who escapes incarceration, rejoins the enemy, and is captured again during combat. Such an individual, according to Article 78, should not be punished for escaping the prison. Rather, he should simply be reincarcerated with the proper measures taken to ensure that a second escape will not be possible.

The final article of Section III addresses proper interrogation techniques. It is to be expected, according to Article 80, that any “honorable” enemy prisoner would be reluctant to provide information to his captors. Still, the Union Army is allowed to question the prisoner by using reasonable techniques to gain such information. Then again, it is the policy of the American government, the article states, that torture or other forms of violence commonly used by armies in the past had no place in the modern military environment, and the army was therefore prohibited from employing such tactics. Furthermore, it is to be expected that a prisoner may give false information to his or her interrogators. Any prisoner who does so, the article states, should not be physically punished for such misdirection.

Communication between Belligerents

According to the articles of Section V of General Orders Number 100, nations in a state of war must have no contact with one another. Such a guideline works to prevent the unlawful acquisition and distribution of information by spies and traitors. Section V begins by stating that two warring nations must cease any sort of communications unless an exception is allowed by the highest levels of government or the military (Article 86). The acceptable representative of one of the combatants in the rival nation is a neutral party or ambassador. However, even diplomats are to be carefully monitored and sanctioned by the “supreme authority” of the government before they are allowed to operate within the country in question, a rule established by Article 87.

As indicated earlier, the use of deceptive tactics in warfare, such as donning the enemy’s uniform, is a practice to be avoided and warrants severe punishment. It is understandable, therefore, that the Lieber Code would apply the death penalty to spies. According to Article 88, any individual who is caught spying on America (even if he or she is unsuccessful in acquiring and distributing information) shall be punished “with death by hanging by the neck.”

Spies are not the only war criminal facing the death penalty in a state of martial law. General Orders Number 100 also references “war-traitors” (individuals who either provide information or otherwise engage in conversation with an enemy without the official sanction of high-level military commanders, as defined in Article 90). “The war-traitor is always severely punished,” states Article 91, adding that any war-traitor found guilty of sharing American troops’ plans, condition, operations, or status may expect the death penalty. Likewise, a citizen of an area invaded or conquered by the enemy and who is cut off from his or her own government by that enemy may expect the death penalty if he or she is found guilty of attempting to divulge information about the enemy to his or her own government.

A major theme that is evident throughout General Orders, No. 100 is not just that the American military must abide by these rules, but that troops can expect that their enemies will follow similar rules. This presumption would be correct, as the Confederates would begrudgingly adopt the general order’s principles. Although war necessarily involves violence and destruction, the Lieber Code was meant to at least create a battlefield in which morality and humanity is present.

Essential Themes

General Orders No. 100 gave some stability to the chaos of war. When the Union proved unsuccessful in toppling Richmond, Virginia, it became clear that neither great restraint nor great brutality were effective policies. The government therefore turned to one of the leading minds on the subject of military law to formally codify for American troops the rules of modern warfare.

The Lieber Code, as it became known, calls for moral and ethical treatment of the enemy and provides justification for certain tactics employed by the US military in its campaign against the Confederates. On the one hand, for example, it discourages the general concept of “giving no quarter,” except in certain survival situations. On the other hand, it advocates sieges, effectively starving an enemy force holed up in a fort or city. Furthermore, the orders disapprove of the wanton destruction of property and life that sometimes occurs in war, including activity that is based on revenge rather than on a discernible objective, but they allow for the intense bombardment of an enemy position and the death penalty for spies.

The Lieber Code was crafted with a focus on the Civil War. However, its limits on the brutal tactics of war have found relevance in other conflicts and the international agreements that resolved them. The Treaty of Versailles and the Geneva Conventions, for example, have some of their roots in the Lieber Code. Although the code could not be seen as a means to avoid war, when adopted (as it has been in other countries), it has proven effective in keeping interstate war from much of the revenge, brutality, and destruction that were commonplace before the Civil War.

  • “Background Document on the Lieber Code.” American Red Cross. International Committee of the Red Cross, 2012. Web. 26 Apr. 2013.
  • Bosco, David. “Moral Principle vs. Military Necessity.” American Scholar. Phi Beta Kappa, 2008. Web. 26 Apr. 2013.
  • “Francis Lieber: A Biography That Is a Thesis upon His Work and Influence.” New York Times. New York Times, 27 Jan. 1900. Web. 26 Apr. 2013.
  • Heidler, David Stephen, and Jeanne T. Heidler. Encyclopedia of the American Civil War: A Political, Social, and Military History. New York: Norton, 2000 Print.
  • Witt, John Fabian. “Lincoln Changes the Rules of War.” American History 47.6 ( 2013): 60–65. Print.
Additional Reading
  • Hartigan, Richard Shelly. Military Rules, Regulations and the Code of War: Francis Lieber and the Certification of Conflict. New Brunswick: Transaction, 2011. Print.
  • Mack, Charles R. Francis Lieber and the Culture of the Mind. Columbia: U of South Carolina P, 2005. Print
  • Neely, Mark E., Jr. The Civil War and the Limits of Destruction. Cambridge: Harvard UP, 2007. Print.
  • Witt, John Fabian. Lincoln’s Code: The Laws of War in American History. New York: Free. 2012. Print.
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