law of war

The law of war is a body of law concerning acceptable justifications to engage in war (jus ad bellum) and the limits to acceptable wartime conduct (jus in bello or International humanitarian law). The law of war is considered an aspect of public international law (the law of nations) and is distinguished from other bodies of law, such as the domestic law of a particular belligerent to a conflict, that may also provide legal limits to the conduct or justification of war.

Amongst other issues, modern laws of war address declarations of war, acceptance of surrender and the treatment of prisoners of war; military necessity, along with distinction and proportionality; and the prohibition of certain weapons that may cause unnecessary suffering.^[1]

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 Hebrew Bible (Old Testament). For example, Deuteronomy 20:19-20 limits the amount of acceptable collateral and environmental damage:

When thou shalt besiege a city a long time, in making war against it to take it, thou shalt not destroy the trees thereof by forcing an axe against them: for thou mayest eat of them, and thou shalt not cut them down (for the tree of the field is man's life) to employ them in the siege: Only the trees which thou knowest that they be not trees for meat, thou shalt destroy and cut them down; and thou shalt build bulwarks against the city that maketh war with thee, until it be subdued.^[2]

Also, Deuteronomy 20:10-12, requires the Israelites to make an offer of peace to the opposing party before laying siege to their city.

When you march up to attack a city, make its people an offer of peace. If they accept and open their gates, all the people in it shall be subject to forced labor and shall work for you. If they refuse to make peace and they engage you in battle, lay siege to that city.^[3]

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.^[4]

In the early 7th century, the first Caliph, Abu Bakr, whilst instructing his Muslim army, 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.^[5][6]

Furthermore, Sura Al-Baqara 2:190-193 of the Koran requires that in combat Muslims are only allowed to strike back in self-defence 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 medieval Europe, the Roman Catholic Church also began promulgating teachings on just war, reflected to some extent in movements such as the Peace and Truce of God. The impulse to restrict the extent of warfare, and especially protect the lives and property of non-combatants continued with Hugo Grotius and his attempts to write laws of war.

The modern law of war is derived from two principal sources:^[1]

• Lawmaking treaties (or conventions) — see the section below called "International treaties on the laws of war".
• 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. (see Martens Clause). Such customary international law is established by the general practice of nations together with their acceptance that such practice is required by law.

Positive international humanitarian law consists of treaties (international agreements) which directly affect the laws of war by binding consenting nations and achieving widespread consent—see the section below called "International treaties on the laws of war".

The opposite of positive laws of war is customary laws of war,^[1] many of which were explored at the Nuremberg War Trials. These laws define both the permissive rights of states as well as prohibitions on their conduct when dealing with irregular forces and non-signatories.

The Lieber Code, promulgated by the Union during the American Civil War, was critical in the development of the laws of land warfare.^[7] Historian Geoffrey Best called the period from 1856 to 1909 the law of war’s “epoch of highest repute.”^[8] 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.^[9] 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"^[10] held, under the guidelines Nuremberg Principles, that treaties like the Hague Convention of 1907, 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 Carla Del Ponte, the chief prosecutor for the International Criminal Tribunal for the former Yugoslavia pointed out in 2001 that although there is no specific treaty ban on the use of depleted uranium 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 violate general principles of the law applicable to use of weapons in armed conflict.^[11] This is because in the future it may be the consensus view that depleted uranium projectiles breaches one or more of the following treaties: The Universal Declaration of Human Rights; the Charter of the United Nations; the Genocide Convention; the United Nations Convention Against Torture; the Geneva Conventions including Protocol I; the Convention on Conventional Weapons of 1980; the Chemical Weapons Convention; and the Convention on the Physical Protection of Nuclear Material.^[12]

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 combatants and noncombatants from unnecessary suffering.
• Safeguarding certain fundamental human rights of persons who fall into the hands of the enemy, particularly prisoners of war, the wounded and sick, and civilians.
• Facilitating the restoration of peace.

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 violence that is not reasonably necessary for military purposes and that belligerents conduct hostilities with regard for the principles of humanity and chivalry.

However, because the laws of war are based on consensus, the content and interpretation of such laws are extensive, contested, and ever-changing.^[13] The following are particular examples of some of the substance of the laws of war, as those laws are interpreted today.

Declaration of war

Main article: Declaration of war

Section III of the Hague Convention of 1907 required hostilities to be preceded by a reasoned declaration of war or by an ultimatum with a conditional declaration of war.

Some treaties, notably the United Nations Charter (1945) Article 2, and other articles in the Charter, seek to curtail the right of member states to declare war; as does the older Kellogg-Briand Pact 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 1949 Geneva Conventions, provide that it is unlawful for belligerents to engage in combat without meeting certain requirements, among them the wearing of a distinctive uniform or other distinctive signs visible at a distance, and the carrying of weapons openly. Impersonating soldiers of the other side by wearing the enemy’s uniform is allowed, though fighting in that uniform is unlawful perfidy, as is the taking of hostages.

Red Cross, Red Crescent and the white flag

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

In either case, persons protected by the Red Cross/Crescent 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 perfidy. Failure to follow these requirements can result in the loss of protected status and make the individual violating the requirements a lawful military 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 armed forces. 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 combat, but they are not guilty of a war crime if a bomb mistakenly hits a residential area.

By the same token, combatants that intentionally use protected people or property as shields or camouflage are guilty of violations of laws of war and are responsible for damage to those that should be protected.

Remedies for violations

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

Soldiers who break specific provisions of the laws of war lose the protections and status afforded as prisoners of war, but only after facing a "competent tribunal" (GC III Art 5). At that point they become an unlawful combatant but they must still be "treated with humanity and, in case of trial, shall not be deprived of the rights of fair and regular trial", because they are still covered by GC IV Art 5. For example in 1976 foreign soldiers fighting for FNLA were captured by the MPLA in the civil war that broke out when Angola gained independence from Portugal in 1975. In the Luanda Trial, after "a regularly constituted court" found them guilty of being mercenaries, three Britons and an American were shot by a firing squad on July 10, 1976. Nine others were imprisoned for terms of 16 to 30 years.

Spies and terrorists may be subject to civilian law or military tribunal for their acts and in practice have been subjected to torture and/or execution. The laws of war neither approve nor condemn such acts, which fall outside their scope.^{[citation needed]} Spies may only be punished following a trial and if captured after rejoining their army must be treated as a prisoner of war.^[14] Suspected terrorists who are captured during an armed conflict, without having participated in the hostilities, may be detained only in accordance with the GC IV and are entitled to a regular trial.^[15] However, nations that have signed the UN Convention Against Torture have committed themselves not to use torture on anyone for any reason. Citizens and soldiers of nations which have not signed the Fourth Geneva Convention are also not protected by it (Article 4: "Nationals of a State which is not bound by the Convention are not protected by it".), whether they are spies or terrorists. Also, citizens and soldiers of nations which have not signed and do not abide by the Third and Fourth Geneva Conventions are not protected by them. (Common Article 2: "[The High Contracting Parties] shall furthermore be bound by the Convention in relation to [a Power which is not a contracting party], if the latter accepts and applies the provisions thereof" (emphasis added).)

If someone is (or is suspected to be) a citizen or soldier of a nation which has signed or abides by the Fourth Geneva Convention (see Art. 2 and Art. 4 citations above), or is (or is suspected to be) a "prisoner of war" (POW) per the definitions of such "protected persons" in the Third Geneva Convention (see Art. 4 and Art. 5), the following applies: A POW who breaks specific provisions of the laws of war may be penalized, but not penalized worse than the tribunal would penalize its own soldiers for the same offense (and usually a disciplinary, not judicial, punishment if its own soldiers normally wouldn't be brought to trial for a particular offense) and POW's may not be penalized based on rank or gender, nor with corporal punishment, collective punishments for individual acts, lack of daylight, or torture/cruelty (GC IV, Art. 82 through Art. 88).

After a conflict has ended, persons who have committed or ordered any breach of the laws of war, especially atrocities, may be held individually accountable for war crimes through process of law. Also, nations which 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. (see GC III, Art. 129 and Art. 130)

History has shown that the laws of war are traditionally more strictly applied to those defeated, as the victorious faction are placed in the role of policing themselves.^{[citation needed]} While it can be argued that the victors may be less strict on their own forces, it can also be argued that the signing of the treaties involved in the laws of war implies a good-faith promise to adhere to them equally.^{[citation needed]} As with many facets of war, the aftermath and subsequent legal proceedings depend heavily on circumstance, and are different for each conflict.

There is an emerging trend in the US to hold private corporations civilly liable for aiding and abetting in war crimes, by knowingly providing substantial assistance in the commission of the crimes. Under international law, the mens rea element is knowledge, not intent that the crimes be carried out. This opens the door not only to hold private security contractors liable, but also other kinds of corporations which employ violent mercenary or terrorist groups as private security forces. Although conflict zones often lack functioning legal systems, and government may even have passed laws immunizing private mercenaries from criminal liability, aiding and abetting a war crime can still be the basis for civil liability in a foreign court with jurisdiction over the defendant corporation.