‘Treaty law’ and ‘customary international law’ are the main sources of international humanitarian law. Treaties, such as the four Geneva Conventions of 1949 and their Additional Protocols of 1977, are written sources in which States formally establish certain rules. Customary international law derives from “a general practice accepted as law”.

The main sources of IHL are:

1- Treaties:

Treaties, such as the four Geneva Conventions of 1949 and the two Additional Protocols of 1977, are written conventions in which States formally establish certain rules. Treaties may also take the form of protocols, covenants, agreements, and so on.

They impose rules only on those States that have expressed their consent to be bound by them.

The Geneva Conventions and their Additional Protocols contain the most important rules limiting the barbarity of war. They protect people who are not taking part in the fighting (civilians, medical personnel, aid workers) and those who can no longer fight (the wounded, sick and shipwrecked troops, prisoners of war).

The 1949 Geneva Conventions:

The First Geneva Convention protects wounded and sick soldiers on land during war.

This Convention is the fourth version of the original 1864 Geneva Convention on the wounded and sick, which was modified in 1906 and then in 1929. It contains 64 articles, which provide protection not only for the wounded and sick, but also for medical and religious personnel, medical units and medical transports.

The Convention also grants formal recognition to the protective emblems.

The Second Geneva Convention protects wounded, sick and shipwrecked members of armed forces at sea during war.

This Convention replaced the Hague Convention of 1907 for the Adaptation to Maritime Warfare of the Principles of the Geneva Convention of 22 August 1864. In terms of structure and content its provisions are very similar to those of the First Geneva Convention. It contains 63 articles, which apply specifically to war at sea. For example, it protects hospital ships.

The Third Geneva Convention applies to prisoners of war.

This Convention replaced the Convention relative to the Treatment of Prisoners of War of 1929. It contains 143 articles. The categories of person entitled to prisoner-of-war status were broadened in accordance with the First and Second Geneva Conventions. Places of detention and the conditions of detention were more precisely defined: particularly with regard to the labour of prisoners of war, their financial resources, the relief they receive, and the judicial proceedings instituted against them. The Convention establishes the principle that prisoners of war must be released and repatriated without delay after hostilities have ended.

The Fourth Geneva Convention
affords protection to civilians, including in occupied territory.

This Convention is composed of 159 articles. It contains a short section that deals broadly with the protection afforded to people against certain consequences of war; however, the conduct of hostilities is not dealt with in this section. The bulk of the Convention deals with the status and treatment of protected per-sons, distinguishing between the situation of foreigners on the territory of one of the parties to the conflict and that of civilians in occupied territory. It spells out the obligations of the Occupying Power vis-à-vis the civilian population and contains detailed provisions on humanitarian relief for persons in occupied territory. It also contains a specific regime for the treatment of civilian internees.

The Additional Protocols:

In the two decades that followed the adoption of the Geneva Conventions, non-international armed conflict and wars of national liberation became more frequent.

In response, two Protocols additional to the four 1949 Geneva Conventions were adopted in 1977.

They strengthen protection for victims of international (Additional Protocol I) and non-international (Additional Protocol II) armed conflicts and place limits on the way wars are fought.

Additional Protocol II was the first international treaty that dealt exclusively with situations of non-international armed conflict.

In 2005, a third Protocol additional to the four 1949 Geneva Conventions was adopted; this created another emblem, the red crystal, which has the same international status as the red cross and the red crescent.

2- Customary International Law:

Customary international law is made up of rules that are considered “general practice accepted as law” and that exist independently of treaty law. Customary IHL is of crucial importance in today’s armed conflicts because it fills gaps left by treaty law applicable to both international and non-international conflicts and so strengthens the protection afforded to victims.

International law is made up of both treaty law and the rules of what is known as customary international law. Treaties are written conventions in which States formally establish certain rules. Customary international law, on the other hand, is not written but derives from “a general practice accepted as law”. A customary rule reflects the practice of states; furthermore, the international community must consider that there is a legal obligation to engage in a practice.

Customary IHL continues to be relevant in today’s armed conflicts for two main reasons. The first is that, while some States have not ratified important treaty law, they remain nonetheless bound by rules of customary law.

The second reason is the relative weakness of treaty law governing non-international armed conflicts – those that involve armed groups and usually take place within the boundaries of one country. A study published by the ICRC in 2005 showed that the legal framework governing internal armed conflicts is more detailed un-der customary international law than under treaty law. Since most armed conflicts today are non-international this is of particular importance.