War is the treaty done between nations to kill the enemy each other legally. No murder punishment no guilty. Various methods are invented to carry the explosive on the opposite, guns, missiles and artillery, etc.
By the way, is there any reason that murder is not a crime? Destruction of the human body is not allowed, no matter who is an enemy or not.
We cannot repair or reborn the living thing that was once destroyed, our scientific research could not reach the point to do that.
God does not forgive to stop the life of human being with any reason.
Even if we create powerful destructive weapons and use them to intimidate others, we will not be able to understand each other.
What is most important is to break the cycle of consistent hatred and look to the future. Without mutual respect between the parties, it is very difficult, for things to work out, really unlikely.
Our desires expand endlessly and never seem to stop, but what we actually need to survive is limited. We don't consume many of the Earth's resources while our span of lives. So, let's stop fighting over things and try to coexist by giving each other what we lack.
Isn't it about time to put an end to the history of massacres and conflicts that has been repeated since prehistoric times?
Haven't we done enough already? Even if we don't kill each other, humans can only live for a hundred years at the longest.
War cost is consumption only, no productivity, it's just wasting of resources.
If we redirected the huge defense and military budget to peaceful uses, the world would be a lot different, far better.