Aerial bombardment and international law

Air warfare must comply with laws and customs of war, including international humanitarian law by protecting the victims of the conflict and refraining from attacks on protected persons. These restraints on aerial warfare are covered by the general laws of war, because unlike war on land and at sea—which are specifically covered by rules such as the 1907 Hague Convention and Protocol I additional to the Geneva Conventions, which contain pertinent restrictions, prohibitions and guidelines—there are no treaties specific to aerial warfare. To be legal, aerial operations must comply with the principles of humanitarian law: military necessity, distinction, and proportionality: An attack or action must be intended to help in the military defeat of the enemy; it must be an attack on a military objective, and the harm caused to civilians or civilian property must be proportional and not excessive in relation to the concrete and direct military advantage anticipated. Before and during World War II (1939–1945), international law relating to aerial bombardment rested on the treaties of 1864, 1899, and 1907, which constituted the definition of most of the laws of war at that time – which, despite repeated diplomatic attempts, was not updated in the immediate run-up to World War II. The most relevant of these treaties is the Hague Convention of 1907 because it was the last treaty ratified before 1939 which specified the laws of war regarding the use of bombardment. In the Hague Convention of 1907, two treaties have a direct bearing on the issue of bombardment. These are "Laws of War: Laws and Customs of War on Land (Hague IV); 18 October 1907" and "Laws of War: Bombardment by Naval Forces in Time of War (Hague IX); 18 October 1907". It is significant that there is a different treaty which should be invoked for bombardment of land by land (Hague IV) and of land by sea (Hague IX). Hague IV, which reaffirmed and updated Hague II (1899), contains the following clauses: Article 25: The attack or bombardment, by whatever means, of towns, villages, dwellings, or buildings which are undefended is prohibited.