War is a phenomenon of organized collective violence that affects either the relations between two or more societies or the power relations within a society. War is governed by the law of armed conflict, also called “international humanitarian law.”
The concept of international humanitarian law goes back to ancient history and exists in every culture, religion, and tradition. It is closely linked to the history of war. In all historical periods, leaders set up rules and taboos that determine what is allowed and what is forbidden in military activities. These rules aim at trying to maintain control, discipline, and efficiency of military forces. They also aim at limiting the impact of violence and destruction on the physical and mental integrity of combatants, in order to facilitate their return to society after the conflict has ended.
The first laws of war were not universal but regional. Indeed, the first Chinese treaty was drafted by Sun Tzu during the sixth to fifth centuries BC. Most of its principles were inspired by religion and aimed at humanizing social, political, and military relationships. However, these rules were enforced only between people of the same cultural background. If the enemies did not speak the same language or were from a different religion, these rules were not respected. The theory of “just wars” or “holy wars” is an illustration of the ambiguity of such a phenomenon. This theory progressively moved from the requirement of “just war” to the requirement of “just means.” Subsequently, European lawyers such as Grotius, Vittoria, or Vattel, as well as Muslim lawyers such as Chaybani, transformed moral standards into legal rules, thereby anticipating contemporary universal codification. It is worth noting that, in the area of jus gentium , important Islamic writings were drafted before—and therefore probably influenced—European codification.
Contemporary international law encompasses these traditions—therefore giving them a universal character. Contemporary international law limits the conditions under which a State may resort to force. It restricts the means and methods of war allowed, regardless of the objectives pursued. ▸ Aggression ▸ Collective security ▸ Security Council of the UN ▸ Self-defense
Throughout the ages, rules have been written and accepted by States to limit the use of force to protect societies from the long-term effects of war, by attempting to prevent conflicts from reaching a point of no return. International law does this by regulating war and prohibiting specific acts and behavior, such as gratuitous massacres and the extermination of civilian populations, which may make a return to peace and reconciliation difficult. It also stresses the importance of distinguishing between civilians and combatants. This is meant for the protection of civilians, as well as to clarify that the use of force that is permitted is not granted to all individuals but must be carried out within a collective and structured organization, under a clear chain of command.
Humanitarian law adjusted to the developments of warfare. Originally, this set of laws concentrated on interstate conflicts where armies of comparable strength fought each other. However, the conflicts in the past fifty years were different. With the wars for decolonization, States and non-state actors claimed legal autonomy. Therefore, conflicts did not oppose traditional State armies. Rather, guerilla activities led by more or less organized non-state actors now intervene in the civil arena. The Cold War led to a “balance of terror,” with no possibility for direct military confrontation between States with nuclear powers. Consequently, conflicts again moved toward the civilian sphere, involving more and more armed non-state actors. The use of terror against civilians has always been a core characteristic of such asymmetrical conflicts.
While first concerned with combatants, humanitarian law has thus moved toward greater protection of civilians and the development of rules applicable to internal conflicts. The law of international armed conflict was codified progressively over the course of hundreds of years. The endurance and constancy of these rules over time means that a number of them are considered “customary,” meaning they are internationally accepted. In other words, they are binding even on States or belligerents that have not formally adhered to such rules.
The roots of positive international law come from a concept of war developed in the nineteenth century. The laws were written by States, and their aim, for the most part, was to regulate interstate wars and to protect the rights of soldiers. The conflicts that took place over the past fifty years no longer clearly fit into that context. Furthermore, humanitarian law has continued to evolve to improve the protection of civilians and reinforce the rules applicable to internal armed conflicts.
This is most clearly expressed in the Fourth Geneva Convention of 1949 and the two 1977 Additional Protocols to these Conventions. Humanitarian law adapts to respond to these fluctuating challenges by according increasing importance to custom—to the practices of States and combatants as well as humanitarian organizations**.** ▸ International humanitarian law ▸ Non-state armed groups
Different Kinds of Conflicts
The word war is no longer used in international law. The term international armed conflict is used when referring to a war between two or more States and non-international armed conflict when referring to a civil war. A certain level and intensity of violence must be reached before a situation is qualified as one of “armed conflict.” Beneath that threshold, violent situations are called “internal disturbances” or “tensions.” Riots, isolated and sporadic acts of violence, and other acts of a similar nature are not considered armed conflicts (APII Art. 1.2).
Humanitarian law only applies to situations of armed conflict. Nonetheless, in cases of internal disturbances and tensions, both human rights and humanitarian law establish certain fundamental guarantees that must be respected. ▸ Fundamental guarantees ▸ Internal disturbances ▸ and tensions ▸ International armed conflict ▸ Non-international armed conflict ▸ Siege
The Parties to a Conflict
In situations of conflict, armed forces use methods of mass violence, in an organized and united manner. The fact that rules exist makes it possible to differentiate between armed conflict and chaos. Combatants must be organized into groups and units that respond to a hierarchy of command, which in turn is responsible for giving orders and ensuring discipline, including compliance with humanitarian law.
Combatants confronting one another may belong to official and recognized political authorities, such as governments, or they may make up the armed forces of a political authority that has not been recognized by the adverse party to the conflict or by other States. This is often the case in wars of national liberation and civil wars, for instance. The law of armed conflict applies to all parties to the conflict, no matter what authority commands them. ▸ Belligerents ▸ Combatants ▸ High Contracting Party ▸ Parties to the conflict ▸ Resistance movements ▸ Situations and persons not expressly covered by humanitarian law ▸ Special agreement
In 1928, States, under the Kellogg-Briand Pact, rejected the option of resorting to war in international relations. This renunciation was short-lived. The UN Charter limits the right to use force in relations between States but does not forbid it completely (States may only use armed force for self-defense, in response to aggression). Instead, they should settle their international disputes through pacific means, with the help of the international community and various mechanisms set up within the UN system to this effect.
In fact, States are under the express obligation to seek peaceful solutions. If pacific attempts fail and international peace and security are threatened, the Charter foresees the possibility of using international armed forces to restore peace. In the past fifty years, such mechanisms have operated in a partial and ad hoc manner, through the different peacekeeping operations that have taken place.
Despite all these restrictions, war remains a component of international relations, as it has since ancient times. ▸ Aggression ▸ Collective security ▸ Peacekeeping ▸ Security Council of the UN ▸ United Nations
Rules of War
The international law of armed conflict was codified progressively over the course of hundreds of years. The philosophy behind such regulation is the same on all continents:
- War is a transitional phase; therefore, it must be conducted in a way that will not make a return to peace impossible, both for society as a whole and for soldiers who must be able to readapt to civilian life.
- The spirit of the rules is consistent: it aims to avoid unnecessary suffering and destruction, and it prohibits acts that are disproportionate to the specific military advantage that is sought. It emphasizes the importance of distinguishing between military and civilian objects.
States have been regulating and limiting the means and methods of warfare since long before the existence of the UN—in the framework of which additional rules governing the use of force have been adopted.
The basic principle is that a military operation is only legitimate if it is a means of attaining a specific military objective. The weapons used must be proportionate and coherent with this objective and must avoid unnecessary destruction and suffering. The method of combat must enable the combatants to distinguish between civilian and military targets. The methods used must also allow aid to be brought to civilian victims during the fighting.
The four 1949 Geneva Conventions and their Additional Protocols of 1977 are the most recent example of the codification of these principles. They regulate the methods of warfare and reaffirm the right to relief for civilians and other non-combatants.
The Right to Violence
Violence, destruction, and killing are regulated by the 1949 Geneva Conventions and the 1899 Hague Conventions through the provisions concerning weapons and methods of warfare. ▸ Attacks ▸ Geneva Conventions and Protocols ▸ Hague Conventions ▸ International humanitarian law ▸ Methods (and means) of warfare ▸ Weapons
The Right to Assistance
The Geneva Conventions and their Additional Protocols establish the details of the protection that must be provided to civilians and the relief to which victims of conflicts are entitled. ▸ Medical duties ▸ Protected objects and property ▸ Protected persons ▸ Protection ▸ Relief ▸ Right of access ▸ Right of humanitarian initiative
The Geneva Conventions and their Additional Protocols also ensure a minimum standard of protection, applicable in any kind of conflict. In particular, these concern the essential rules governing relief and protection for civilians. ▸ Fundamental guarantees
The Geneva Conventions also establish States’ specific responsibilities, as well as those of the commanders of armed forces and of individuals, in terms of the implementation and respect for the rules of humanitarian law. They also establish the different penal sanctions that can be applied to punish war crimes or other crimes against humanity. ▸ Attacks ▸ Duty of commanders ▸ Penal sanctions in humanitarian law ▸ Proportionality ▸ Respect for international humanitarian law ▸ Responsibility ▸ War crimes/Crimes against humanity
For Additional Information: Gray, Christine. “The Use of Force and the International Legal Order.” In International Law , edited by Malcolm D. Evans, 589–620. Oxford: Oxford University Press, 2003.
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