Customary IHL – helping to improve the protection of victims of armed conflict

What is customary international humanitarian law?  

Customary international humanitarian law is a set of unwritten rules derived from a general, or common, practice which is acknowledged as law. It's the basic standard of conduct in armed conflict accepted by the world community. Customary international humanitarian law is applicable universally – independently of the application of treaty law – and is based on extensive and virtually uniform State practice regarded as law.  

In the 1990s, at the request of the international community, the ICRC undertook an extensive study into current State practice in international humanitarian law in order to identify customary law in this area. Before the study was published, no comprehensive written analysis and compilation of customary IHL rules existed. The study has contributed to identifying the common core of international humanitarian law binding on all parties to all armed conflicts.  Today, the ICRC’s Customary IHL Database makes these rules and the commentaries thereto easily accessible and searchable.   
 

There are already many treaties covering armed conflict. Why is customary IHL important?  

Customary international humanitarian law is important because its rules, and compliance therewith, can reduce the human cost of armed conflict. It complements the protection provided for conflict victims by treaty law, and fills in certain gaps resulting from treaties not having been ratified by certain States or from treaty law lacking detailed rules on non-international armed conflict.  

Although the 1949 Geneva Conventions have been universally ratified, for example, other treaties of international humanitarian law, such as the 1977 Additional Protocols or the 1997 Ottawa Convention banning anti-personnel mines, have not. As a result, victims of armed conflict, particularly those affected by non-international armed conflict, are not always fully protected by treaty law. That is why it was necessary to determine which rules are part of customary law and therefore applicable to all parties to a conflict, regardless of their treaty obligations.  
In addition, a large proportion of today's armed conflicts are non-international, and treaty-based international humanitarian law doesn't regulate them in sufficient detail. These conflicts are subject to far fewer treaty rules than are international conflicts. For example, the 1949 Geneva Conventions contain 344 substantive articles dealing with international armed conflicts and just one regulating non-international conflicts. Similarly, the 1977 Additional Protocol II, covering non-international armed conflicts, contains a mere 15 substantive articles, whereas Additional Protocol I, dealing with international armed conflicts, has 84.   

It was important, therefore, to determine whether customary international law regulates non-international armed conflict in more detail than does treaty law. The conclusions of the ICRC study are that the basic rules on the conduct of hostilities, on the use of means and methods of warfare and on the treatment of persons in the hands of a party to a conflict are fully applicable in non-international armed conflicts.
Out of the 161 rules identified by the Study, 146 were deemed to apply in both international and non-international armed conflicts. From a practical perspective, knowing that many rules apply in both kinds of conflict is particularly helpful when there is doubt or controversy on the legal qualification of a conflict as international or non-international. Moreover, the general applicability of customary IHL – as opposed to the applicability of treaty law, which is subject to ratification of specific treaties – is very useful in, say, situations where parties to the conflict have not ratified the same treaties or where military operations are carried out by multinational forces, composed of troops from a variety of States that have not all ratified the same treaties and so, to put it simply, are not all playing by the same rule book.     

How are the customary IHL study and database being used?  

Both the study and the database have been used in various ways by a whole range of entities. First and foremost, the ICRC has used the study as an important legal reference in international and non-international armed conflicts. The organization refers to it in its dialogue with parties to conflict in order to identify humanitarian rules by which combatants or parties must abide.  

The study and the database have also been used by the United Nations, international and mixed courts and tribunals with jurisdiction over violations of IHL, national courts dealing with war crimes cases, and non-governmental organizations advocating better respect for IHL or which monitor violations of the law. To give one concrete example: on the basis of practice collected for the study, the Special Court for Sierra Leone concluded that the recruitment of child soldiers is a war crime in non-international armed conflicts, thus enhancing the protection for children being recruited and used as child soldiers.  
In addition, the reports of UN Special Rapporteurs on the conflicts in southern Lebanon (2006) and Gaza (2009) relied on the study to identify the customary rules of international humanitarian law applicable in those conflicts.  

In many States customary international law – or the practice underlying its rules – can be invoked before national courts and tribunals. In Israel, for example, the Supreme Court delivered a judgment in 2008 concerning restrictions on the flow of fuel and electricity to Gaza. The court referred to customary IHL and the ICRC study which stated that "each party to a conflict is obliged to refrain from disrupting the passage of basic humanitarian relief to populations needing it in areas under its control."     

Has the database developed much since it was launched in 2010?  

Certainly – the formation of customary law is a dynamic process. The original study included practice up until 2003 and that practice has not ceased to evolve. Moreover, we observe greater interest for, and more discussion on, IHL, including on the existence, scope and meaning of customary rules of IHL. As States and other actors express themselves more frequently and in greater detail on IHL matters, this generates more practice, both at the domestic and at the international level.  
In order to monitor the evolution of customary IHL, the ICRC teamed up with the British Red Cross Society to update the practice underlying the rules identified by the study. The ICRC recognized the need for the research to be available as a resource for anyone following the developments in the application and interpretation of international humanitarian law and for any future weighing of State practice in the assessment of customary international humanitarian law.
The ICRC’s Customary IHL Database offers all who work with or are interested in IHL a tool that consolidates the source materials into one resource, accessible free of charge and worldwide, and provides users with subject-specific analysis tools. It is easy to navigate and its lay-out and search engine allow users to select and bring together extracts of national and international practice that are relevant for a specific subject-matter.  

How does the database work and what is its added-value for those working on issues related to armed conflict and IHL?  

In addition to providing the full text of the study, presented per chapter and per rule, the database also allows practitioners and academics to carry out research using three main search parameters: country, type of practice and subject matter. Using the advanced search function, one can thus look up what a particular State has included in its military manuals, legislation and/or case law about any of the topics covered in the study.

For example, a search for relevant national case law on civilians’ loss of protection from attack when directly participating in hostilities currently provides the user with relevant extracts from eight judgments delivered by the domestic courts of Colombia, Germany, Israel, the USA and Venezuela. A search on the protection of medical personnel in the Central African Republic brings up relevant extracts from the Central African Republic Ministry of Defence Instructors’ Manual of 1999 and Disciplinary Regulations of 2009 stating that during combat medical personnel must be respected and protected. A visit to the international tribunals section of the page with practice related to rape and other forms of sexual violence offers the user relevant extracts from 39 arrest warrants and judgments of six international tribunals dealing with different elements of rape as a war crime or a crime against humanity in both international and non-international armed conflicts.  

The other significant advantage of the database is the possibility to regularly update practice without having recourse to a print publication.  Updating practice allows the ICRC to monitor and evaluate further developments of customary IHL, thereby preparing the road for a future revision of Volume I of the original study. Also, the continued collection of practice will provide additional evidence to make conclusions on the existence, scope and meaning of some of the more controversial rules identified by the 2005 study.

But the collection of practice and its thematic analysis has also proved increasingly useful in itself, both for the ICRC and for others working in the field of armed conflict and IHL. The collection of national practice, translated into English, on a wide variety of IHL issues is of precious value in the ICRC’s protection dialogue where it allows the ICRC to rely on concrete national legislation, case law, military doctrine or other country-specific practice in its dialogue with national authorities.

The wealth of national practice in the database is also very useful in supporting the planning and implementation of prevention strategies and activities, which focus on the dissemination of IHL, its implementation in domestic law and its integration into the training of and instructions to armed forces.

Finally, the data collected and analysed, on a wide variety of specific IHL topics, allows the ICRC to identify trends that can inform its activities in the field of clarification and development of the law. In this way, the database is very useful for projects such as the updating of the Commentaries to the Geneva Conventions and their Additional Protocols, strengthening legal protection of victims of armed conflict and the Healthcare in Danger project as well the ICRC’s activities in the area of weapons law.

The fundamental aim remains, however, to achieve better protection of the victims of armed conflict; the ongoing investment in the customary IHL database is not an end in itself but an important tool in efforts to achieve that goal.