Recent events around the world remind us of historical phenomena observed since the dawn of civilizations: wars, genocides, oppression, conquests, occupations, and, of course, killings in the name of some God. Although the underlying principles are the same, modern killings are more sophisticated, spectacular, and effective than those in the past. In a matter of hours, you can now hijack a plane and crush it against an office building killing thousands, or you can (as it was done more than 50 years ago) drop an atomic bomb over a city killing hundreds of thousands of civilians. You can see all that on TV.
Studying non-human animals, contemporary biology, evolutionary theory, and modern ethology have gathered enough knowledge to respond to questions regarding the nature of aggression, social power, alliance formation, hierarchical domination, and attack-defense behavior. Psychology, anthropology and cognitive science have added important pieces extending this knowledge into human animals. From these studies contemporary science has got some deep understanding about what peace is about. In a nutshell, the moral is that there is no absolute, ideal or ultimate peace in the animal kingdom. Peace turns out to be a fragile local phenomenon that depends on circumstances, population density, biological needs, availability of resources, and so on. If you value peace, the best you can do is to provide conditions for peace, not to "install" peace itself.
So, if we have good scientific knowledge about the nature of peace, how come we don't have peace on earth? Well, because we don't want to accept that we are animals. We prefer to continue believing that we are the protégées of our own created Gods, and that we are, in a transcendental sense, different from a chimpanzee. Peace for humans is taken to be something profound, spiritual and pure, not a bio-social emerging phenomenon. Our created Gods provide the moral values that define what the absolute and ultimate peace is supposed to be, and who is supposed to impose it. There is no surprise then if we see intransigent world and religious leaders calling for holy wars, fighting the Evil in the name of the Good, and justifying in the name of peace, the bombing of civilians, the construction of missile shields, or the occupation of foreign territories.
If we really value peace (but I am not sure this is what some world powers really want!), what we need is to provide sustainable conditions for peace. And for this, it would be much easier to know how to do it, if we assume once for all, that we are indeed animals.