Distinction (law) in the context of "Protocol I to the Geneva Conventions"

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.

The formal concept of war crimes emerged from countries fighting and 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 1899 and 1907 for international war. In the aftermath of World War II, the war-crime trials of the leaders of the Axis powers established the Nuremberg principles, such as that international criminal law defines what is a war crime. In 1899, the Geneva Conventions legally defined new war crimes and established that states could exercise universal jurisdiction over war criminals. In the late 20th century and early 21st century, international courts extrapolated and defined additional categories of war crimes applicable to a civil war.

Proportionality is a general principle in law which covers several separate (although related) concepts:

• The concept of proportionality is used as a criterion of fairness and justice in statutory interpretation processes, especially in constitutional law, as a logical method intended to assist in discerning the correct balance between the restriction imposed by a corrective measure and the severity of the nature of the prohibited act.
• Within criminal law, the concept is used to convey the idea that the punishment of an offender should fit the crime.
• Under international humanitarian law governing the legal use of force in an armed conflict, proportionality and distinction are important factors in assessing military necessity.
• Under the United Kingdom's Civil Procedure Rules, costs must be "proportionately and reasonably incurred", or "proportionate and reasonable in amount", if they are to form part of a court ruling on costs.

The principle of proportionality means that belligerents must not launch an attack when the anticipated death and injury to civilians is clearly excessive in light of the military advantage expected from the attack.

Military necessity, along with distinction, and proportionality, are three important principles of international humanitarian law governing the legal use of force in an armed conflict.

A war crime is a serious violation of the laws and customs applicable in armed conflict, known as international humanitarian law (IHL) and the laws of war, which gives rise to criminal responsibility under international law. Examples of actions committed by combatants in the conduct of war that can give rise to individual criminal responsibility include, but are not limited to: intentionally killing civilians, torture, taking hostages, unnecessarily destroying civilian property, deception by perfidy, wartime sexual violence, pillaging, the granting of no quarter despite surrender, the conscription of children in the military, ordering any attempt to commit mass killings (including genocide or ethnic cleansing), and flouting the requirements of distinction, proportionality and military necessity.

The formal concept of war crimes emerged from countries fighting and the codification of the customary international law that applied to warfare between sovereign states, such as the 1863 Lieber Code of the Union Army in the American Civil War and the Hague Conventions of 1899 and 1907 for international war. In the aftermath of the Second World War, the war crime trials of the leaders of the Axis powers established the Nuremberg principles, such as that international criminal law defines what is a war crime. In 1899, the Geneva Conventions legally defined new war crimes and established that states could exercise universal jurisdiction over war criminals. In the late 20th century and early 21st century, international courts extrapolated and defined additional categories of war crimes applicable to a civil war.