Four years later, a most unusual event took place in Athens and was faithfully recorded by Thucydides, the most reliable of the ancient historians. The citizens of Athens, then a self-consciously democratic society, voted in their Assembly, following a speech by the rabble-rousing Cleon, that the rebellious city state of Mytilene, which had now been subdued, should pay, in the name of justice, an exemplary penalty. All its adult males should be executed without trial, and its women and children sold into slavery. Acts of genocide were by no means unusual at the time, being committed by both Athens and Sparta: Histiaca, Melos, Scione and Torone were examples. But this was the first and I think the only time genocide was authorised, after debate, by a formal vote in a democratic body, by roughly the same people who had seen Medea four years before. To the honour of Athens, the very next day the leader of the moderates, Diodotus, persuaded the Assembly to cancel the order, and a fast trireme was dispatched to Myteline with the revised instructions, fortunately arriving in time to prevent the massacre. But Diodotus had to concede the justice of the original order, and defend its annulment on grounds of expediency. It was left to Socrates, who was almost certainly present at the votes, and indeed at the performance of Medea, to argue conclusively that retaliation was objectively wrong and could not possibly be a principle of justice. Socrates's argument was gradually accepted, at any rate by some people, for by the time Aristotle came to write his Nichomachean Ethics, he singled out the Pythagoreans as unusual in that they defined "justice" as "reciprocity". 

The debate between Socrates and Pythagoreans has continued, in various ways, ever since, and is currently taking all kinds of tormented forms in the war against Islamic fundamentalism, which — it is worth noting — is regarded by many Islamists, even in its extreme suicide-bomb form, as mere retaliation. There may or may not be such a thing as a "just war". But we can be sure that war, which means the abandonment of reason, justice to individuals, and proportion, cannot be fought justly, as Burleigh demonstrates time and again. All that a morally self-respecting society can do is to try to ensure that obvious excesses are prevented. 

As Burleigh shows, both Germany and Japan failed in this respect, more or less totally. Even worse, in some ways, than the extermination camps, were the activities of large SS squads of 500-1,000 men instructed to carry out mass-murder during the early stages of the Russian campaign, since the individual often had to take personal decisions about who to kill and how to do it. Himmler's orders to units often reflect a confused but sharp moral sense. Thus he strictly forbade troops to steal cigarettes from civilians they had just murdered. Burleigh cites cases of the more callous troops being indicted as "excess perpetrators", examples being drunk Ukrainian militiamen who held "pigeon shoots" by throwing babies into the air, and a man found unconcernedly eating his lunch using the naked body of a dead Jewish woman as a chair. 

Burleigh presents the Japanese as even worse. They exterminated small tribes like the Suluks on Borneo as well as female Australian nurses on Banka Island. Captured airmen were deliberately killed, cooked and eaten: cannibalism was practised on a large scale, of what was deemed necessity but also for symbolic purposes. A B-29 crew was subjected to live, unanaesthetised vivisection in a university hospital, where their organs were removed one by one until they died. But Burleigh thinks that General Tojo's instruction to POW camp officers "not to be obsessed by a mistaken idea of humanitarianism" proved that cruelty was not culturally determined. Few will follow him on that point.