"At the start of the Second World War, there were still some questions, at least on the Allied side, about what constituted a legitimate target (a British Cabinet minister is said to have protested in 1939, ‘But that’s private property,’ when the possibility of bombing German industry in the Ruhr came up). The all-out nature of the war swept such issues aside, although, again on the Allied side, they never completely disappeared. All the belligerents used bombing of civilians to disrupt enemy war efforts and weaken the will to fight on. Ports, factories, railway marshalling yards, oil depots, dams and bridges were all targets, but so too were housing and city centres. Hermann Goering promised Hitler in the summer of 1940 that he could force Britain to sue for peace by bombing its airfields and key cities, especially London. Sir Arthur Harris, chief of Britain’s Bomber Command, was convinced, and managed to persuade his superiors, including Winston Churchill, that the war against Germany could be won by the bomber and that the critical target was German morale."