It is an odd bit of cognitive dissonance among most people today that killings of innocent people by police are (rightly) treated as moral outrages, while killings of innocent civilians by militaries are often rationalized as “collateral damage” – unfortunate, perhaps, but such is war, and the greater cause of the war is said to justify them. Ayn Rand, for instance, made the argument that all of the civilian deaths in a war are the moral fault of the aggressor regime.
One need not look to the battlefield to see clear instances of unjustified initiation of force. There exist numerous acts of criminal aggression within a country’s borders, with regard to which the kind of arguments that are used to justify war would be readily seen as faulty. There is still a lot of murder in every country. Suppose there is a murderer on the loose. Would it be justified for a country’s domestic police force to send a missile into or plant a bomb in a large and inhabited apartment building, simply because the murderer is believed to be hiding there? Would the answer change if this murderer were a serial killer who has already had a string of victims and/or plans to kill more?
I think virtually everyone would agree that inflicting civilian casualties to eliminate this murderer would not be appropriate and would not be worth the moral cost. Virtually nobody would make the argument that it is the murderer, not the police force, who would be morally responsible for any civilian deaths – and therefore it would be acceptable for the police to act to bring about civilian deaths, and to plan for some civilian deaths in advance, and to simply describe these deaths as regrettable “collateral damage”. Virtually everybody in that situation would agree that the police who permit innocent civilians to die in the capture or destruction of the murderer would themselves bear the blame for the clearly preventable deaths of those civilians.
So why is the situation any different just because the word “war” is used to describe a particular instance of aggression – and just because the people involved are not all from the same country and may be acting outside the borders of their country? Aggression is aggression, and the leaders of an invading dictatorships are criminals just like serial killers, except on a larger scale. My view is that the same moral principles should apply to the proper response to all of them. The proper moral response is to neutralize the threat, but to leave the innocent people out of it entirely. No innocent death should ever be dismissed as mere “collateral damage” – and no plan should be pursued if it is known or expected to result in innocent deaths.