A war crime is a violation of the laws of war that gives rise to individual criminal responsibility for actions by combatants in action, such as intentionally killing civilians or intentionally killing prisoners of war, torture, taking hostages, unnecessarily destroying civilian property, deception by perfidy, wartime sexual violence, pillaging, and for any individual that is part of the command structure who orders any attempt to committing mass killings including genocide or ethnic cleansing, the granting of no quarter despite surrender, the conscription of children in the military and flouting the legal distinctions of proportionality and military necessity.
[1] In 1474, the first trial for a war crime was that of Peter von Hagenbach, realised by an ad hoc tribunal of the Holy Roman Empire, for his command responsibility for the actions of his soldiers, because "he, as a knight, was deemed to have a duty to prevent" criminal behaviour by a military force.
[2][3] The Hague Conventions were international treaties negotiated at the First and Second Peace Conferences at The Hague, Netherlands, in 1899 and 1907, respectively, and were, along with the Geneva Conventions, among the first formal statements of the laws of war and war crimes in the nascent body of secular international law.
The Lieber Code was written early in the American Civil War and President Abraham Lincoln issued as General Order 100 on April 24, 1863, just months after the military executions at Mankato, Minnesota.
[4] 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.
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 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.
[11] To date, the present and former heads of state and heads of government that have been charged with war crimes include: War crimes are serious violations of the rules of customary and treaty law concerning international humanitarian law, criminal offenses for which there is individual responsibility.
[29] Colloquial definitions of war crime include violations of established protections of the laws of war, but also include failures to adhere to norms of procedure and rules of battle, such as attacking those displaying a peaceful flag of truce, or using that same flag as a ruse to mount an attack on enemy troops.
[35] Article 30 of the 1907 Hague Convention IV – The Laws and Customs of War on Land explicitly forbids belligerents to punish enemy spies without previous trial.
[47] Controversy arose when the Allies re-designated German POWs (under the protection of the 1929 Geneva Convention on Prisoners of War) as Disarmed Enemy Forces (allegedly unprotected by the 1929 Geneva Convention on Prisoners of War), many of which were then used for forced labor such as clearing minefields.
[49][50] The United Nations defines war crimes as described in Article 8 of the Rome statute, the treaty that established the International Criminal Court:[51][52] Under the law of armed conflict (LOAC), the death of non-combatants is not necessarily a violation; there are many things to take into account.
On the other hand, an extraordinary military advantage would be necessary to justify an operation posing risks of collateral death or injury to thousands of civilians.
For this reason, States have chosen to apply a "clearly excessive" standard for determining whether a criminal violation has occurred.
For aerial strikes, pilots generally have to rely on information supplied by external sources (headquarters, ground troops) that a specific position is in fact a military target.