International humanitarian law purports to regulate the conduct of armed conflict in two key respects. First, it imposes minimum standards of protection for victims of armed conflict, whether they are injured combatants, prisoners of war, or civilians who happen to be caught up in the conduct of armed hostility. The key instruments dealing with this area of the law are the four Geneva Conventions of 1949, which have among the highest number of states parties of all multilateral treaties and the two Additional Protocols of 1977. Secondly, International Humanitarian Law restricts the permissible means and methods of warfare, including the types of weapons that can be deployed and the targets they can be deployed against, and limits the amount of force used to what is proportionate to the legitimate military necessity.
The Geneva Conventions 1949 are only applicable to international armed conflicts, and common article 3 alone extends some of the basic principles to internal armed conflicts. In the 1970s, as the international community was negotiating new instruments to extend and develop further the rules of international humanitarian law, it was recognized that internal armed conflicts posed a particular challenge to the application of these rules. The two Additional Protocols of 1977 were created to extend the minimum standards of humanitarian protection for victims of armed conflict, and the scope of the rules dealing with means and methods of warfare. Somewhat controversially, Additional Protocol I applies to international armed conflicts, including struggles for self determination against ‘colonial domination and alien occupation and against racist regimes’. Additional Protocol II extends some of the rules of international humanitarian law to internal armed conflicts not otherwise covered by Additional Protocol I. However, a number of problems have arisen among states’ reactions to this approach.