The Western illusion of human nature as either grim and savage (bad) or noble and harmonious (good) still has not recovered from the shock of Pierre Clastres' work. Basically, he agrees that societies without a state are structurally dependent on regularly waging war, but he does not conclude as the other Hobbesians that this necessarily is a good reason for a sovereign. In fact, according to Clastres, the reason why these societies constantly wage war is exactly to ward of the sovereign. It should not come as a surprise that this position is extremely awkward in the debate between the various Hobbes- and Rousseau-like figures we in the West have had to listen argue for the last past 2500 years or at least since the time of the fool Thycudides. Or how about the Founding Fathers, e.g. the title of young John Adams' unpublished essay: "All men would be tyrants if they could". Well, it seems not. But according to Clastres, it is not because these societies are inherently peaceful (or angel-like), it is because they are organized against tyranny: the chief is forced to speak (so the society is given the opportunity to ignore him), the warriors are entirely dependent on the honor given to them by society (so they can easily take it from him, if he begins to desire power over them), a chief who begins to desire too much power can be forced to seek more and more dangerous ways of being honored (finally driving him into a suicide mission) etc. etc. One can see how this does not fit nicely into any existing position in the above mentioned debate. Also, it is not so much a hypothesis of human nature as it is about a way of organizing society. Or as Marshal Sahlins might have said, the natural propensity for humans to create many kinds of culture. Consequently, Clastres is still very much ignored.

Some literature to continue on this path:
Marshal Sahlins, The Western Illusion of Human Nature. The above-mentioned 2500 year old debate between bad and good human nature reduced to a three hour lecture. With some comparative notes on societies that do neither.
David Graeber deals with him in Fragments of an Anarchist Anthropology (and introduces the crucial idea, that the reason many egalitarian societies without a state know of domination often is because men dominate the women, a topic overlooked by Clastres).
* Tiqqun, 'Sorrows of the Civilised Warrior' in This Is Not A Programme being particularly inspired by him. And other texts.