However, the Additional Protocols to the Geneva Conventions adopted in 1977 containing the most pertinent, detailed and comprehensive protections of international humanitarian law for persons and objects in modern warfare are still not ratified by several states continuously engaged in armed conflicts, namely the United States, Israel, India, Pakistan, Iraq, Iran, and others. Every single member state of the United Nations has currently ratified the conventions, which are universally accepted as customary international law, applicable to every situation of armed conflict in the world. The Geneva Conventions are four related treaties adopted and continuously expanded from 1864 to 1949 that represent a legal basis and framework for the conduct of war under international law.
The formal concept of war crimes emerged from the codification of the customary international law that applied to warfare between sovereign states, such as the Lieber Code (1863) of the Union Army in the American Civil War and the Hague Conventions of 18 for international war. A war crime is a violation of the laws of war that gives rise to individual criminal responsibility for actions by the combatants, such as intentionally killing civilians or intentionally killing prisoners of war torture taking hostages unnecessarily destroying civilian property deception by perfidy rape pillaging the conscription of child soldiers committing genocide or ethnic cleansing the granting of no quarter, despite surrender and flouting the legal distinctions of proportionality and military necessity.