Over on the other side of the world, Hitler's Axis ally waged what was depicted as a war of liberation so as to free their fellow Asians from European and US colonialism in South-East Asia and the Pacific. Churchill specifically excluded that sort of liberation from the terms of the Atlantic Charter. The Japanese message had considerable purchase among nationalists in these regions, many of whom indirectly benefited from Japanese mobilisation of populations with the slogan "Asia for the Asians". Sukarno in the Dutch East Indies would be a good example of an Asian collaborator, or a nationalist who exploited the Japanese, but it also applied to much of the Filipino elites and Wang Jinwei in Nationalist China. 

While none of these people objected to the white man being slapped around, things went awry when the Japanese slapped around Asians too, or requested Malay Muslims to bow towards Tokyo once a day rather than to Mecca. 

The Japanese found themselves fighting counter-insurgency wars, to which the victorious imperialists after 1945 were indebted for the term "winning the people's hearts" ("minshin haaku", in Japanese), as well as the strategic hamlets and other tactics used in Indochina, Indonesia, South Korea and Malaya in the following decade. In some cases, the Allies used captured Japanese troops to reimpose the colonial power — Gracey in Indochina being an example — or, as in South Korea, found their Military Advisory Group advising men who had served in the Japanese armed forces.

In this minor attempt to reclaim the history of morality in warfare from the philosophers and theologians, or at least men in white coats who bloodlessly scrutinise impossible real-time decisions, perhaps I should conclude by reverting to the world of the young Christopher Seton-Watson. He fought in three very different theatres — northern France, North Africa and Italy. 

Physical context often determined how wars were fought, for in this respect the Second World War is an umbrella term for several types of conflict. In North Africa, there were few civilians, no partisans and the fluid nature of the fighting in featureless terrain militated against the more intimate violence troops went on to experience in Italy and France. 

It may have helped that neither Hitler nor the Americans regarded the desert war as much more than an unwelcome detour, forced on them by their Italian and British allies. What one might call the circumstantial spiral of violence took off in the altogether trickier terrain of Italy and northern France with its opportunities for booby-traps and close-quarter combat. Seton-Watson recorded in April 1945 that after a Polish officer disappeared, only for his mutilated corpse to be found later, orders were published to accept no German paratroops as prisoners, and to shoot even those retained for interrogation. "Cold-blooded" Poles may have done the shooting, but British officers also tacitly sanctioned activities which lessened the possibility of enemy surrenders. 

The pre-ordering of the legal framework, a high degree of ideological investment, and a relentless spiral of violence, explain why the German-Soviet war was fought with appalling brutality on both sides, or rather all sides, since Romanians were responsible for some of the worst massacres. Even the Einsatzgruppen affected professional disdain for what they saw the Romanians do in Odessa, the largest single massacre of Jews in Europe. In 1944, what was normative behaviour on the Eastern Front leeched on to the Western Front: SS divisions did things in France which they had done every day of the week, month in month out, in the Soviet Union. That habit rebounded on the perpetrators.