When the second World War ended in 1945 and the full, horrifying scale of Nazi depravity became evident, they said it would never be allowed happen again, writes David Adams.
The victorious allies even established the United Nations to try and ensure that it didn't.
It seems perverse in the extreme, now, to think that two of the principal signatories to the UN charter were China and the Soviet Union.
In fact, along with the United Kingdom and the United States, they helped draft the original proposals on which the charter is based.
In hindsight, it was a bit like inviting Dr Harold Shipman to help draw up a code of practice for care of the elderly. At the time, "Uncle Joe" Stalin was well on his way to murdering tens of millions of his fellow citizens. Mao Tse-tung was only four years away from grabbing absolute power in China; allowing him and his cohorts to begin paving the road to their own utopia with millions of Chinese corpses.
Despite fine sounding words, with that kind of example being set from the beginning, it should hardly surprise that state-sponsored murder on an industrial scale has never stopped happening. The practices (if not always the ideology) of the Nazis have progressively spread like a virus around the world.
False imprisonment, rape, torture and the mass killing of innocents by those in power have become commonplace. In many regions, it takes little to mark you down for death: the "wrong" ethnicity, religion, colour or political outlook is usually more than enough. Those of an independent mind or considered a potential threat to an imposed and all-pervading orthodoxy, are usually the first to go.
Just some of the killing fields, past and present, that spring most readily to mind are China, the USSR, Cambodia, Vietnam, Iran, Iraq, South Africa, Rhodesia, Rwanda, Burundi, Zimbabwe, the Congo, Sudan, the Middle East, North Africa, the Balkans, South America and many of the republics and provinces of the former Yugoslavia.
In truth, the list is well nigh endless and the scale of human suffering and death beyond imagining. God alone knows what is happening to the powerless in inaccessible places such as North Korea. Neither should we think that this propensity for extreme violence is analogous with any particularities pertaining to race, intellect, education, religious adherence, cultural background or even sanity: a perusal of the most infamous actors will disabuse of any notions in that direction.
We appropriate the Robert Burns line "man's inhumanity to man" to describe the wanton butchery - but we only kid ourselves.
The word "inhumanity" suggests that what is happening is somehow outside the realms of normal human inclination. But, if incidence is anything to go by, mankind's propensity for extreme violence and cruelty is all too basic and, in that sense, an intrinsic part of our make- up. It is held in check only by the enforcement (or threat of it) of man-made and thereby wholly unnatural rules and regulations, whose origins lie in our earliest attempts to form communities beyond the immediate family. When these collapse or are removed we soon revert to type and the most basic rule of the jungle, survival of the strongest, prevails once more. If this butchery is ever to be stopped, then we must ensure that rules and regulations cannot be set aside so easily. There must be a non-negotiable and strictly enforced code of behaviour that every national administration is required to abide by.
Power, wherever it resides and no matter who wields it, must always be accountable. The UN was supposed to protect the helpless: it has failed dismally. Its practice of imposing economic sanctions on rogue nations is counterproductive in the extreme. How many citizens starve to death before a dictator is forced to go without sugar in his tea? It intervenes in the internal affairs of a sovereign nation only when it considers that genocide (the policy of deliberately killing a nationality or ethnic group) is being practised there.
But aside from providing no protection to millions of people in danger of being deliberately murdered for reasons other than nationality or ethnicity, and only becoming involved after mass killings have taken place, the terminology is so imprecise and open to interpretation that, in practice, politics rather than need decides where and when the UN intervenes. For the most part, national sovereignty simply means that any dictator or regime so inclined has a licence to kill fellow citizens with impunity.
If the weak are to be protected from the strong, then every individual must be considered, first and foremost, to be a citizen of the world: protected by and accountable to the rest of us. Using as it does the same criterion for intervention, the only obvious differences between the recently established International Criminal Court and UN war crimes courts are its permanent status and the fact that it doesn't enjoy the support of the US.
State-sponsored murder on an industrial scale will continue until the world community declares "this will not happen again" - and actually means it.