Law of war

The law of war refers to the component of international law that regulates the conditions for () and the conduct of warring parties (jus in bello). Laws of war define sovereignty and nationhood, states and territories, occupation, and other critical terms of international law.

Among other issues, modern laws of war addresses the, acceptance of and the treatment of ; , along with  and ; and the prohibition of certain  that may cause unnecessary suffering.

The law of war is considered distinct from other bodies of law—such as the of a particular belligerent to a conflict—which may provide additional legal limits to the conduct or justification of war.

Early sources and history
Attempts to define and regulate the conduct of individuals, nations, and other agents in war and to mitigate the worst effects of war have a long history. The earliest known instances are found in the and the.

In the Indian subcontinent, the Mahabharata describes a discussion between ruling brothers concerning what constitutes acceptable behavior on a battlefield, an early example of the rule of proportionality:

"One should not attack chariots with cavalry; chariot warriors should attack chariots. One should not assail someone in distress, neither to scare him nor to defeat him ... War should be waged for the sake of conquest; one should not be enraged toward an enemy who is not trying to kill him."

An example from the 20:19–20 limits the amount of acceptable collateral and environmental damage:

"19When you besiege a city for a long time, making war against it in order to take it, you shall not destroy its trees by wielding an axe against them. You may eat from them, but you shall not cut them down. Are the trees in the field human, that they should be besieged by you? 20Only the trees that you know are not trees for food you may destroy and cut down, that you may build siegeworks against the city that makes war with you, until it falls." Also, Deuteronomy 20:10–12, requires the Israelites to make an offer of peace to the opposing party before laying siege to their city."10 When you draw near to a city to fight against it, offer terms of peace to it. 11And if it responds to you peaceably and it opens to you, then all the people who are found in it shall do forced labour for you and shall serve you. 12 But if it makes no peace with you, but makes war against you, then you shall besiege it."

Similarly, Deuteronomy 21:10–14 requires that female captives who were forced to marry the victors of a war could not be sold as slaves.

In the early 7th century, the first, , whilst instructing his , laid down the following rules concerning warfare:

"Stop, O people, that I may give you ten rules for your guidance in the battlefield. Do not commit treachery or deviate from the right path. You must not mutilate dead bodies. Neither kill a child, nor a woman, nor an aged man. Bring no harm to the trees, nor burn them with fire, especially those which are fruitful. Slay not any of the enemy's flock, save for your food. You are likely to pass by people who have devoted their lives to monastic services; leave them alone."

Furthermore,  2:190–193 of the  requires that in combat Muslims are only allowed to strike back in  against those who strike against them, but, on the other hand, once the enemies cease to attack, Muslims are then commanded to stop attacking.

In the history of the early Christian church, many Christian writers considered that Christians could not be soldiers or fight wars. contradicted this and wrote about '' doctrine, in which he explained the circumstances when war could or could not be morally justified.

In 697, gathered Kings and church leaders from around Ireland and Scotland to, where he gave them the '', which banned killing women and children in war, and the destruction of churches.

In, the also began promulgating teachings on , reflected to some extent in movements such as the. The impulse to restrict the extent of warfare, and especially protect the lives and property of s continued with and his attempts to write laws of war.

One of the grievances enumerated in the was that King  "has endeavoured to bring on the inhabitants of our frontiers the merciless Indian Savages whose known rule of warfare is an undistinguished destruction of all ages, sexes and conditions".

Modern sources
The modern law of war is made up from three principal sources:


 * Lawmaking  (or conventions)—see below.
 * Custom. Not all the law of war derives from or has been incorporated in such treaties, which can refer to the continuing importance of customary law as articulated by the . Such is established by the general practice of nations together with their.
 * General Principles. "Certain fundamental principles provide basic guidance. For instance, the principles of distinction, proportionality, and necessity, all of which are part of customary international law, always apply to the use of armed force".

consists of (international agreements) that directly affect the laws of war by binding consenting nations and achieving widespread consent.

The opposite of positive laws of war is customary laws of war, many of which were explored at the. These laws define both the permissive rights of states as well as prohibitions on their conduct when dealing with and non-signatories.

The signed on November 25 and 26, 1820 between the president of the,  and the Chief of the Military Forces of the , , is the precursor of the International Humanitarian Law. The, signed and ratified by the United States and Mexico in 1848, articulates rules for any future wars, including protection of civilians and treatment of prisoners of war. The, promulgated by the Union during the , was critical in the development of the laws of land warfare. Historian Geoffrey Best called the period from 1856 to 1909 the law of war's "epoch of highest repute." The defining aspect of this period was the establishment, by states, of a positive legal or legislative foundation (i.e., written) superseding a regime based primarily on religion, chivalry, and customs. It is during this "modern" era that the international conference became the forum for debate and agreement between states and the "multilateral treaty" served as the positive mechanism for codification.

In addition, the Nuremberg War Trial judgment on "The Law Relating to War Crimes and Crimes Against Humanity" held, under the guidelines, that treaties like the , having been widely accepted by "all civilised nations" for about half a century, were by then part of the customary laws of war and binding on all parties whether the party was a signatory to the specific treaty or not.

Interpretations of international humanitarian law change over time and this also affects the laws of war. For example,, the chief prosecutor for the pointed out in 2001 that although there is no specific treaty ban on the use of  projectiles, there is a developing scientific debate and concern expressed regarding the effect of the use of such projectiles and it is possible that, in future, there may be a consensus view in international legal circles that use of such projectiles violates general principles of the law applicable to use of weapons in armed conflict. This is because in the future it may be the consensus view that depleted uranium projectiles breach one or more of the following treaties: ; the ; the ; the ; the including ; the  of 1980; the ; and the.

Purposes of the laws
It has often been commented that creating laws for something as inherently lawless as war seems like a lesson in absurdity. But based on the adherence to what amounted to customary international law by warring parties through the ages, it was felt that codifying laws of war would be beneficial.

Some of the central principles underlying laws of war are:
 * Wars should be limited to achieving the political goals that started the war (e.g., territorial control) and should not include unnecessary destruction.
 * Wars should be brought to an end as quickly as possible.
 * People and property that do not contribute to the war effort should be protected against unnecessary destruction and hardship.

To this end, laws of war are intended to mitigate the hardships of war by:
 * Protecting both s and s from unnecessary suffering.
 * Safeguarding certain fundamental of persons who fall into the hands of the enemy, particularly, the wounded and sick, children, and.
 * Facilitating the restoration of.

Principles of the laws of war
', along with ', and , are three important principles of governing the legal use of force in an armed conflict.

Military necessity is governed by several constraints: an attack or action must be intended to help in the defeat of the enemy; it must be an attack on a, and the harm caused to civilians or civilian property must be proportional and not excessive in relation to the concrete and direct military advantage anticipated.

Distinction is a principle under international humanitarian law governing the legal use of force in an armed conflict, whereby s must distinguish between s and s.

Proportionality is a principle under international humanitarian law governing the legal use of force in an armed conflict, whereby belligerents must make sure that the harm caused to civilians or civilian property is not excessive in relation to the concrete and direct military advantage expected by an attack on a legitimate military objective.

Example substantive laws of war
To fulfill the purposes noted above, the laws of war place substantive limits on the lawful exercise of a belligerent's power. Generally speaking, the laws require that belligerents refrain from employing that is not reasonably necessary for military purposes and that belligerents conduct hostilities with regard for the principles of  and.

However, because the laws of war are based on consensus, the content and interpretation of such laws are extensive, contested, and ever-changing. The following are particular examples of some of the substance of the laws of war, as those laws are interpreted today.

Declaration of war
Section III of the required hostilities to be preceded by a reasoned  or by an ultimatum with a conditional declaration of war.

Some treaties, notably the (1945) Article 2, and other articles in the Charter, seek to curtail the right of member states to declare war; as does the older  of 1928 for those nations who ratified it.

Lawful conduct of belligerent actors
Modern laws of war regarding conduct during war (jus in bello), such as the, provide that it is unlawful for belligerents to engage in combat without meeting certain requirements, such as wearing distinctive or other distinctive signs visible at a distance, carrying weapons openly, and conducting operations in accordance with the laws and customs of war. Impersonating enemy combatants by wearing the enemy's uniform is allowed, though fighting in that uniform is unlawful, as is the taking of s.

Combatants also must be commanded by a responsible officer. That is, a commander can be held liable in a court of law for the improper actions of his or her subordinates. There is an exception to this if the war came on so suddenly that there was no time to organize a resistance, e.g. as a result of a.

People parachuting from an aircraft in distress
Modern laws of war, specifically within, prohibits regardless of what territory they are over. Once they land in territory controlled by the enemy, they must be given an opportunity to surrender before being attacked unless it is apparent that they are engaging in a hostile act or attempting to escape. This prohibition does not apply to the dropping of, , , , , s, and. Thus, such personnel descending by parachutes are legitimate targets and, therefore, may be attacked, even if their aircraft is in distress.

Red Cross, Red Crescent, Magen David Adom, and the white flag
Modern laws of war, such as the 1949 Geneva Conventions, also include prohibitions on attacking, s or s displaying a , a , , , or other emblem related to the. It is also prohibited to fire at a person or vehicle bearing a, since that indicates an intent to surrender or a desire to communicate.

In either case, people protected by the Red Cross/Crescent/Star or white flag are expected to maintain neutrality, and may not engage in warlike acts. In fact, engaging in war activities under a protected symbol is itself a violation of the laws of war known as. Failure to follow these requirements can result in the loss of protected status and make the individual violating the requirements a lawful target.

Applicability to states and individuals
The law of war is binding not only upon States as such but also upon individuals and, in particular, the members of their. Parties are bound by the laws of war to the extent that such compliance does not interfere with achieving legitimate military goals. For example, they are obliged to make every effort to avoid damaging people and property not involved in or the, but they are not guilty of a war crime if a bomb mistakenly or incidentally hits a residential area.

By the same token, combatants that intentionally use protected people or property as or  are guilty of violations of the laws of war and are responsible for damage to those that should be protected. The use of in warfare has been an especially tricky situation for the laws of war. Some scholars claim that private security contractors appear so similar to state forces that it is unclear if acts of war are taking place by private or public agents. has yet to come to a consensus on this issue.

Remedies for violations
During conflict, for violating the laws of war may consist of a specific, deliberate and limited violation of the laws of war in.

After a conflict ends, persons who have committed or ordered any breach of the laws of war, especially atrocities, may be held individually accountable for through process of law. Also, nations that signed the Geneva Conventions are required to search for, then try and punish, anyone who has committed or ordered certain "grave breaches" of the laws of war. (, Article 129 and Article 130.)

Combatants who break specific provisions of the laws of war are termed. Unlawful combatants who have been captured may lose the status and protections that would otherwise be afforded to them as, but only after a "" has determined that they are not eligible for POW status (e.g., Third Geneva Convention, Article 5.) At that point, an unlawful combatant may be interrogated, tried, imprisoned, and even executed for their violation of the laws of war pursuant to the domestic law of their captor, but they are still entitled to certain additional protections, including that they be "treated with humanity and, in case of trial, shall not be deprived of the ." ( Article 5.)

For example, in 1976, foreign soldiers fighting for the (FNLA) were captured by the People's Movement for the Liberation of Angola  during the  in 1975. In the, after "a regularly constituted court" found them guilty of being unlawful , three Britons and an American were shot by a on July 10, 1976. Nine others were imprisoned for terms of 16 to 30 years.

International treaties on the laws of war
List of declarations, conventions, treaties, and judgments on the laws of war:
 * 1856 abolished.
 * 1864 for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field.
 * 1868 Renouncing the Use of Explosive projectiles Under 400  grams Weight.
 * 1874 Project of an International Declaration concerning the Laws and Customs of War . Signed in Brussels 27 August. This agreement never entered into force, but formed part of the basis for the codification of the laws of war at the 1899.
 * 1880 Manual of the Laws and Customs of War at . At its session in Geneva in 1874 the appointed a committee to study the Brussels Declaration of the same year and to submit to the Institute its opinion and supplementary proposals on the subject. The work of the Institute led to the adoption of the Manual in 1880 and it went on to form part of the basis for the codification of the laws of war at the 1899 Hague Peace Conference.
 * 1899 consisted of three main sections and three additional declarations:
 * I – Pacific Settlement of International Disputes
 * II – Laws and Customs of War on Land
 * III – Adaptation to Maritime Warfare of Principles of Geneva Convention of 1864
 * Declaration I – On the Launching of Projectiles and Explosives from Balloons
 * Declaration II – On the Use of Projectiles the Object of Which is the Diffusion of Asphyxiating or Deleterious Gases
 * Declaration III – On the Use of Bullets Which Expand or Flatten Easily in the Human Body
 * 1907 had thirteen sections, of which twelve were ratified and entered into force, and two declarations:
 * I – The Pacific Settlement of International Disputes
 * II – The Limitation of Employment of Force for Recovery of Contract Debts
 * III – The Opening of Hostilities
 * IV – The Laws and Customs of War on Land
 * V – The Rights and Duties of Neutral Powers and Persons in Case of War on Land
 * VI – The Status of Enemy Merchant Ships at the Outbreak of Hostilities
 * VII – The Conversion of Merchant Ships into War-ships
 * VIII – The Laying of Automatic Submarine Contact Mines
 * IX – Bombardment by Naval Forces in Time of War
 * X – Adaptation to Maritime War of the Principles of the Geneva Convention
 * XI – Certain Restrictions with Regard to the Exercise of the Right of Capture in Naval War
 * XII – The Creation of an International Prize Court [Not Ratified]*
 * XIII – The Rights and Duties of Neutral Powers in Naval War
 * Declaration I – extending Declaration II from the 1899 Conference to other types of aircraft
 * Declaration II – on the obligatory arbitration
 * 1909 largely reiterated existing law, although it showed greater regard to the rights of neutral entities. Never went into effect.
 * 1922 The, also known as the Five-Power Treaty (6 February).
 * 1923 Hague Draft Rules of Aerial Warfare. Never adopted in a legally binding form.
 * 1925 for the Prohibition of the Use in War of Asphyxiating, Poisonous or Other Gases, and of Bacteriological Methods of Warfare.
 * 1927–1930.
 * 1928 (also known as the Pact of Paris).
 * 1929.
 * 1929.
 * 1930 (22 April).
 * 1935.
 * 1936 (25 March).
 * 1938 Amsterdam Draft Convention for the Protection of Civilian Populations Against New Engines of War. This convention was never ratified.
 * 1938 declaration for the "Protection of Civilian Populations Against Bombing From the Air in Case of War."
 * 1945 (entered into force on October 24, 1945).
 * 1946 Judgment of the International.
 * 1947 formulated under  21 November 1947.
 * 1948.
 * 1949.
 * 1949.
 * 1949.
 * 1949.
 * 1954.
 * 1971 Zagreb Resolution of the Institute of International Law on Conditions of Application of Humanitarian Rules of Armed Conflict to Hostilities in which the United Nations Forces May be Engaged.
 * 1974 United Nations.
 * 1977 United Nations.
 * 1977 Additional to the Geneva Conventions of 12 August 1949, and Relating to the Protection of Victims of International Armed Conflicts.
 * 1977 Additional to the Geneva Conventions of 12 August 1949, and Relating to the Protection of Victims of Non-International Armed Conflicts.
 * 1978 Red Cross Fundamental Rules of International Humanitarian Law Applicable in Armed Conflicts.
 * 1980 United Nations (CCW).
 * 1980 Protocol I on Non-Detectable Fragments.
 * 1980.
 * 1980 Protocol III on Prohibitions or Restrictions on the Use of Incendiary Weapons.
 * 1995.
 * 1996.
 * (Protocol V to the 1980 Convention), 28 November 2003, entered into force on 12 November 2006.
 * 1994 on International Law Applicable to Armed Conflicts at Sea.
 * 1994 ICRC/UNGA Guidelines for Military Manuals and Instructions on the Protection of the Environment in Time of Armed Conflict.
 * 1994 UN.
 * 1996 The  on the.
 * 1997.
 * 1998 (entered into force 1 July 2002).
 * 2000 (entered into force 12 February 2002).
 * 2005 Additional to the Geneva Conventions of 12 August 1949, and Relating to the Adoption of an Additional Distinctive Emblem.
 * 2008 (entered into force 1 August 2010).