The rules and principles are applicable regardless of the legality or justness of the conflict, and even if operations are undertaken by way of punitive or police action in the name of the United Nations. The humanitarian principles that operate during armed conflict are to be found in customs originally based on rules of chivalry as between the feudal orders of knighthood. To a great extent these humanitarian principles are to be found in Article 3 common to the Geneva Conventions of 1949. Broadly speaking, they amount to the basic and minimum conditions underlying the rule of law as understood in modern society. Whether the Hague and Geneva Conventions are regarded as codificatory of customary or creative of new law, they are not and do not purport to be exhaustive.
During World War II, because of the intensive bombing attacks experienced by the civilian population, some, like the United Kingdom, set up trained units to work in the field of civil defence, assisting those injured or rendered homeless because of air raids. Civilian civil defence personnel may carry light individual weapons for their own protection or to preserve order, but not weapons like fragmentation grenades or those intended for non-human targets. Military personnel assigned to civil defence duties may perform the duties only within their own national territory and must not commit any act outside those duties which might be inimical to the adverse party. If the parties to the conflict are not parties to the Protocol they are not bound by any treaty regulations concerning the activities or rights pertaining to civil defence.
One of the oldest rules of the law of war provides for the protection of the civilian noncombatant population and forbids making civilians the direct object of attack. The Geneva Convention IV applies only to civilians in the hands of or under the physical control of an adverse party or an Occupying Power. Those in their own territory are protected only by the general rules limiting warlike acts and methods of combat. As with other protected persons, civilians in enemy hands, whether in national or occupied territory, are entitled to respect for their persons, honour, family rights, religious convictions and practices, manners and customs. When imposing punishment it must be remembered that non-national civilians owe no allegiance to the Detaining Power, which nevertheless retains the right to punish offences against its security.
A military aircraft would be one 'operated by commissioned units of the armed forces of a state having the military marks of that state commanded by a member of the armed forces, and manned by a crew subject to regular armed forces discipline'. Military aircraft has the right to fly over international waters and to use such flights for surveillance or photographing another state's territory, even including its military installations. Military aircraft brought down by a neutral state or which land in neutral territory should be detained by the neutral until the end of the conflict and then returned to their home state. Personnel on board such aircraft should be interned until the cessation of hostilities. The general rules regarding the use of weapons forbidding those which cause unnecessary suffering apply in air warfare.
The law of armed conflict has its origins in both customary and conventional law. Though the object of an armed conflict is to achieve victory over the adverse party with the least possible expenditure of men, resources and money, principles of humanity remain relevant. In conducting hostilities the opposing forces should be guided by three basic principles: necessity, humanity and chivalry. Perhaps the most significant international agreement relating to a specific weapon is the 1925 Geneva Gas Protocol. Without specifying any particular weapon, in 1976 a Convention was adopted on the Prohibition of Military or any other Hostile Use of Environmental Modification Techniques. It is forbidden to use starvation as a weapon against the civilian population, but it is lawful to take steps necessary to deprive the adverse party of his food supplies.
Problems have arisen since the adoption of the United Nations Convention on the Law of the Sea (UNCLOS). If it is suggested that UNCLOS constitutes lex generalis it must be indicated that it cannot invalidate any rights arising under lex specialis such as the law of armed conflict, unless there is incontrovertible evidence in the text that it was intended to override such lex specialis. When deciding whether a ship was trading with an enemy port, or whether its cargo was intended for an adverse party, Prize Courts developed the doctrines of continuous voyage and ultimate destination. In maritime warfare only properly authorised combatants are permitted to participate in warlike activities. By Hague Convention VI enemy merchant ships in ports of the adverse party at the outbreak of hostilities were allowed to depart and were granted a period of grace for the purpose.
It has been accepted since antiquity that some restraint should be observed during armed conflict. This book examines the apparent dichotomy and introduces any study of the law of armed conflict by considering the nature and legality of war. The purpose of what is known as the law of armed conflict or, more commonly, the law of war is to reduce the horrors inherent therein to the greatest extent possible, bearing in mind the political purpose for which the war is fought, namely to achieve one's policies over one's enemies. The discussion on the history and sources of the law of armed conflict pays most attention to warfare on land because that is the region for which most agreements have been drawn up, although attention has been accorded to both aerial and naval warfare where it has been considered necessary. Traditionally, international law was divided into the law of war and the law of peace, with no intermediate stage between. Although diplomatic relations between belligerents are normally severed once a conflict has commenced, there remain a number of issues, not all of which are concerned with their inter-belligerent relations, which require them to remain in contact. War crimes are violations of the and customs of the law of armed conflict and are punishable whether committed by combatants or civilians, including the nationals of neutral states. The book also talks about the rights and duties of the Occupying Power, civil defence, branches of international law and prisoners of war.
By the Middle Ages the power of the Church was such that it was able to forbid Christian knights from using certain weapons as hateful to God. In fact, the feudal knights were aware of what they knew as 'the law of chivalry'. The 'law of chivalry' was a customary code of chivalrous conduct that controlled the knight's affairs, which was enforced by arbitrators specially appointed or, in England and France, by Courts of Chivalry. Contrary to the Geneva Law is the law concerning means and methods of conducting actual military operations in armed conflict. This is known as Hague Law, although it had its origin in a conference of fifteen European states called in Brussels at the invitation of Czar Alexander II of Russia. Another instrument that seems to have been applied as expressing accepted law, even though it never received a single ratification, is the Declaration of London.
Traditionally, international law was divided into the law of war and the law of peace, with no intermediate stage between. When hostilities began, usually following a declaration of war, and non-parties to the conflict were held by the belligerents to be subject to the duties of, and they claimed the rights pertaining to, neutrals, war was recognised and the law of war came into operation. As with the situation under customary law, it is irrelevant whether the conflict is in accordance with the obligations of Hague Convention III, the Pact of Paris or the Charter of the United Nations. Even if the conflict does not amount to war in the legal sense of that term, there is nothing in international law, other than human rights conventions, preventing a country imposing restrictions upon the freedom of residents possessing adverse-party nationality.
The relations between a belligerent government and the adverse party's nationals are regulated partly by international and partly by national law. Civilians in the adverse party's territory are treated broadly speaking in accordance with the provisions of the national law, and while their freedom of movement may be restricted their treatment overall must be in accordance with Geneva Convention IV. If the capitulation relates to the surrender of an inhabited place, it may contain stipulations concerning the treatment of the civilian population. Conditions in a capitulation should relate only to the immediate purpose of effecting the surrender and not contain terms which would forbid the surrendered personnel from carrying arms in the future, for that is a political and not a military issue. Passports may be granted by a commander on his own authority or in accordance with his own military law.