Long before the Iraq war, I pondered the value of war.
Many bad things have been said about war- the horror and the useless of it all. And with a modern war the final result could be the entire destruction of all human life; the 20,000 or more nuclear warheads, couldn't really bring about complete extinction, but it certainly could kill billions and could make nuclear weapons the preferred way to conduct war and given enough effort and including the radioactive aspect this extinction could be "achieved". The nuclear weapon has the capacity bring about extinction unlike other older types of weapons which lack the power to bring this about. Of course, there are also biological weapons which could possibly bring about human extinction perhaps quicker and more efficently.

Faced with the prospects of extinction, war seems to have even less value- unless one is so twisted that the entire human existance is regarded as a bad thing.
War has probably been an activity that humans have engaged in before we were human- we know other primates engage in warfare, so it's reasonable that even before we evolved into humans we were warring. Warfare is one group of creatures trying to control another group of creatures. War is using violence or threatening to use force.

In considering the value of war, one can consider the possiblity of whether human could exist at all without any kind of war. I think if you have a human population in an area and you allow enough time AND the humans are interacting with each other, the evenual result will be warfare. I think that laws are created as a response to warfare, and that the purpose of laws are to ultimately deter warfare. There is evidence that supports this and I have little doubt it. BUT I believe that it goes further than this, I believe that without war, that the laws will evenually break down with the evenual breakdown of laws the end result will be warfare.

Therefore the only way to peaceful world is by making laws and ensuring that these laws are enforced [followed]. I do think that even with "perfect" laws and constant attention to the need of enforcing these laws, that war will still result if given enough time (in order of centuries of time). Therefore I believe that war will always be part of human existance- though I think we can certainly reduce the number and frequency of warfare that we currently have. And perhaps given enough time and attention we could *possibly* "evolve" our understanding to a point that war could be avioded for all time [but I have serious doubts about whether this is possible].

Therefore the "good of war" is that in order to aviod war, laws are developed, and these laws enable large societies to interact peacefully, advance culturally and technologically AND *perhaps* this will evenually lead to time in which wars are no longer neccessary.