The sources of IHL

What began with one modest idea from Henry Dunant has evolved over the past century and a half into a complex, specialised and important area of international law that regulates conduct in wartime.

Nowadays, the rules of international humanitarian law are found in over a hundred treaties. Many of these legal agreements, which are signed by countries, are dedicated to regulating particular issues in warfare. For instance, there are treaties that prohibit the use of certain weapons: a Chemical Weapons Convention – banning the use of chemical weapons in wartime; the Ottawa Treaty – a convention prohibiting the use of anti-personnel land mines. There are other agreements that prohibit the use of certain military tactics, and which protect certain categories of people and property.

These specific treaties are significant sources of IHL. Nevertheless, the heart of IHL can be found in more general treaties – treaties you might have heard us mention already, the Geneva Conventions.

As you’ve learned already, the four Geneva Conventions were adopted in 1949, in the aftermath of World War II, at an international conference of diplomats in Geneva. Nearly every State in the world has agreed to be bound by them. Since then, the Conventions have been developed and supplemented by further agreements, significantly the two Additional Protocols of 1977 relating to the protection of victims of armed conflicts. Each of these treaties contain general provisions that regulate the means and methods of warfare. They place limits on what one can do when waging war. At their heart lies a simple but profound premise: a need to, at all times, recognise and respect everyone’s humanity – even one’s enemies.

The following sections will continue to unpack the substance of IHL, but before we turn to them one final thought on the sources of law, that is, where to find them. We have noted that IHL can be found in treaties – international agreements that are written down and signed up to by States. However, there is an additional source of IHL to be aware of: customary international humanitarian law.

Customary IHL can be a difficult concept to wrap your head around – even for international lawyers. It’s a curious aspect of how international law works. Put simply, repeated and consistent practice in armed conflict by States can become accepted and recognised as universally legally-binding rules, after which the failure of a State to respect that particular custom, whether they have signed a corresponding treaty or not, will be a violation of IHL.

This can be thought of in a similar vein to long-standing traditions, customs and practices of a particular group. They may not be written down, but they are entrenched elements of how that group interacts. Customary IHL serves to complement and fill certain gaps in the protection provided to victims of armed conflict under treaty law.

Many provisions of international humanitarian law – including rules found in the Geneva Conventions and their Additional Protocols – are now accepted as customary IHL. For instance, the principle of distinction between civilians and combatants, which you will learn about next; the prohibition of torture, cruel or inhuman treatment; and the rule of respect and protection for medical personnel. This status reflects the fundamental considerations of humanity upon which IHL is based and its widespread acceptance across the globe.