War crimes are the most serious violations of international humanitarian law arising out of an armed conflict. They include such actions as indiscriminate killing not justified by a legitimate military objective, attacking civilians not participating in the conflict, and starving people as a weapon of war. The rules for preventing these offenses are set out primarily in four 1949 treaties that virtually every country accepts, and they constitute the core of secular international law on the conduct of war.
In order to punish war criminals, prosecutors must be able to identify such acts. But that is not always easy. In addition to being a technical legal term, the term “war crime” also carries with it a range of emotive connotations. It signals that the behavior alleged is not just unjustified and illegal, but inherently wicked or despicable. It signals that the perpetrator is a monster in the most literal sense of the word.
For example, suppose a senior army officer in the midst of a counterinsurgency operation becomes enamored with a local woman delivering supplies to his forward operating base. After she rebuffs his advances, he brutally strikes and strangles her to death. The officer has committed a grave breach of the laws of war and is a war criminal. This is because the murder was not in furtherance of an armed conflict, but rather because of his sexual appetite.
The 1949 Geneva Conventions provide a first definition of war crimes, but this has since been expanded and refined through the Additional Protocols to the 1949 treaties and subsequent jurisprudence by international criminal tribunals. In 2019, the Assembly of States Parties to the Rome Statute adopted a new definition applicable in non-international armed conflicts (NIAC) that prohibits as a war crime the intentional starvation of civilians by depriving them of objects indispensable to their survival, including the willful impediment to relief supplies.