The question of why we need enemies has been much discussed in various disciplines, and one interesting idea is that we project bad stuff out onto them. Of course, this has huge implications, for example, with regard to scapegoating and religion. I am thinking of Girard, who argued that Christianity is based on this, and in fact, other religions. So I need an enemy in order to feel good about myself, and to expel the bad from myself. But then in the end, I can bring it back and integrate it, if I am lucky. This happens in war, I suppose, where I become very violent (total war), but it's their fault. But it gets more complicated still, because sometimes I need an enemy in order to feel bad about myself, as they persecute me, and I want to be punished. Ooh la la. Other theories are available.
