"The concept of a just war emerged, suggesting that war is justified only when it meets certain preconditions: if it is waged as a last resort or in self-defense; if the force used is proportional; and if, whenever possible, civilians are spared from violence." said Barrack Obama in his speech accepting the Nobel peace prize. It echoes a feeling often repeated, that war could be more "just" or "morally acceptable" if civilian casualties are low or even absent. I think this is a rather dangerous sentiment. Let me try to present my reasons below.
Let me start with the following statement, "Killing is unacceptable, except for food". I would include killing of all kinds, whether people or animals. Many people may question this premise, but I consider this the basic "law" of nature. No animal kills another except for food, and I am yet to hear of an animal killing another of its kind for whatever reason (even for food). I am supported by the popular saying in India that translates roughly as, "You are absolved of the sin of killing if you eat it".
If killing, except for food, is unacceptable, then killing a person, for whatever reason, is unacceptable. This would include killing even the worst criminals. This may be difficult for many people to accept, but I don't see any way in which we could morally justify killing even a serial killer. We could, perhaps, find reasons based on other considerations, but not on moral ones. This becomes a difficult question and I shall try to look deeper into it later. But right now let me proceed with the problem of the morality of 'civilian deaths' and 'military deaths'.
Why do we feel that civilian deaths cannot be justified? I can think of only two reasons: i) civilians are unarmed and defenceless, so it is not fair to attack them; and, ii) they are not directly involved in war. Let us analyse these reasons. Yes, civilians are generally unarmed. They are not trained to fight. So they do not get a fair chance to defend themselves. But, does this mean that soldiers can be killed because they are armed? Because it is "you or me"? This is true in hand-to-hand combat, especially as in olden days when people used to fight with swords or spears, the better man survives. But, in today's world where one could be killed by a shell fired from kilometres away, by a land mine or a bomb dropped from an aircraft (or even a cruise missile fired from the other side of the globe), this argument does not seem to be valid. It is not one-to-one fight any longer. The individual soldier, however brave he is, or however good a fighter he is, simply has no chance against the killing power of the opposite army. So it hardly matters whether a soldier is armed or thoroughly trained in warfare. Anyone could get killed in a war irrespective of whether he is armed or not.
But, yes, soldiers are directly involved in any war. In a way, wars are all about killing the soldiers of the other party. But everyone would agree, I hope, that that is not the end. A war is almost always about territory - land and the people who live there. So, it is really about the civilians and the power over them. Soldiers are merely "civilians" who take the responsibility to defend the territory. And, of course, the land and the civilians provide them support in the form of food, medicines, arms and ammunition and an assurance of a comfortable retired life if they are not killed. No army can survive without support (voluntary or forced) from land and people. That is why cutting off supply routes is one of the important tactics adopted in any war. In other words, we cannot deny that it is the countries that are at war, the lands and the peoples, not just the militaries.
I hope this won't be interpreted to be a justification for killing civilians. I am trying to say that killing soldiers is as bad. Killing human beings, especially in the name of war, is totally avoidable. No other animal on earth indulges in such cruel and wasteful activities. And the death of a person, whether a soldier or not, is equally painful to his/her family. Nothing can really compensate for the death of a person. In my opinion, it is this pain inflicted on people, often people who never wanted any war, that makes killing immoral. And that pain remains the same, whether the person who died is a civilian or a soldier.
Most people in any country would want peace, and not war, except in certain situations. Such situations are often caused by a few people in search of power. While at one time it was the kings who wanted to expand their empires, today it is again such megalomaniacs who create wars. The difference is that today, perhaps, more wars are started also for economic reasons - access to resources or markets. But that is just another kind of power. Of course, wars could also be triggered by the actions of a country that cause problems for a neighbouring country. Even these, I think, could be avoided if global pressure could be brought on such countries.
Apart from all this, we need to remember that wars waste a lot of resources - resources that could have gone to reduce hunger and malnutrition. I am not aware of any study in that direction, but, possibly, climate change would have been less severe if the fuel used for all the wards during the twentieth century had been saved. We are already talking about peak oil (oil production reaching a peak before declining), and people have started talking about such peaks related to other resources (even water!). And the environmental wounds caused by a war takes a pretty long time to heal. We certainly cannot afford to go on causing such extensive (and intensive) damage to our environment.
So rulers of the major countries need to sit and decide about abolishing war. It cannot be just about nuclear weapons. A nuclear war today can easily lead to total destruction of the life on earth. So, talking about using nuclear weapons is like talking about suicide. One good part about suicide is that one does not survive and suffer. But conventional war is more like a failed suicide attempt where the person suffers serious injury that maims him for life. He has to live and bear it. Let us not do that.