Principle of reciprocity and liability transparency

I outlined a scenario before about two nations going to war. One of these nations is an unjust invader of another nation's territory. Call the aggressive unjust nation "Eveville," and the nation they invade "Utopia." Meanwhile, Eveville has a neighboring country call it, "Switzerland" that is neutral in the matter. In the following scenario, the situation is a little different than the original blog's but the situations are still similar and I will draw two distinctive lines of possible ways of thinking about the right of two nations to defend itself from each others military acts when both nations are just actors.

Now most (excluding hardlined pacifists) would argue that Utopia has a right to defend itself against unjust invasion and occupation even if it uses deadly means. I agree. Assume that we are right. Now Utopia is a poor country and the only means of defense they have is using crude weapons which may foreseeably harm the citizens of Switzerland (the weapons used may go astray or the damage done extend to and kill a few Swiss) when implemented in defense against their neighbors Evevillians upon the later's invasion. Let's assume that Utopians have no other plausible means defend themselves.

The question is, does the Swiss have a right to "defend" themselves against the Utopians in their defensive measures which may unintentionally but foreseeably harm the Swiss? I will call the Utopians in this scenario an "innocent threat" because they pose a threat to the Swiss but in doing so, they are merely acting innocently because their intention is only to defend themselves against the aggressive military actions of the Evevillians.

To summarize, the Evevillians launch an unjust attack on the Utopians. Utopians then counter attack but that counter caries significant risk of death to many of Eveville's neighbors, the neutral Swiss. The question is does the Swiss have a right to attack Utopia to try and stop Utopian's defense of itself against Eveville?

Now some may say that the Swiss has a right to defend themselves against the (defensive) actions of the Utopians even by deadly means if the risk their citizens will be killed by a stray or overextending defensive measure is used by the Utopians against the Evevillians. But does the Utopians have a right to then attack Switzerland to counter this counter measure? Some may say that that is also permissible. In other words, some would say that both are permissible to attack each other. But some would go on to say that though both are permitted to attack each other, only one side may be justified. This would depend on how great the harm posed by the invasion of Utopia is. If the harm is greater than the the calculated risk of unintentional harm inflicted on the Swiss, only the Utopians are justified in attacking the Swiss to prevent them from defending themselves against.

I want to now propose a principle here called the principle of reciprocity. This principle is based on counterfactual reasoning. If the Swiss were in the same position, the "same shoes," ceteris paribus, as the Utopians, i.e., they were being unjustly attacked by the Evevillians, would they think it justified to defend themselves even at great cost to a neutral country (say, the Utopians which has the reversed relationship to the Swiss in this counterfactual)?

If the answer is 'yes', then there is reciprocity and the Swiss may not justly attack the Utopians to stop their defensive attack on the Evevillians. If the answer if 'no' then they may. This principle has a distinctly contractarian flavor. What is permissible and justified depends on what parties would do if they had switched roles, if "the shoe was on the other foot".

But I think there are other options besides the principle that we should also consider. Perhaps we could also think that the Swiss do not have the right to attack the Utopians but do have a right to attack Eveville for it is Eveville that initiated this spiral of violence forcing Utopia into a defensive position but also putting the Swiss in grave danger of a defensive attack that overextends the harmful effects to them as a neutral neighbor. So the Swiss cannot maintain their neutrality because the aggressive unjust behavior directed at others also ultimately will affect it in adverse ways. In other words, perhaps the Swiss ought to see Eveville's attack on Utopia as "transferring" to its own territory, as an indirect attack on Switzerland. Thinking it as an indirect attack on its own nation will then destroy its conception as a neutral neighbor and thereby force it to see itself as a participant in being unjustly attacked. This will then give it the right to attack Eveville or to assist Utopia in her defensive actions.

I prefer the last conception of just war. My example shows with this tricky dilemma of the limitations of an isolationist and neutral mindset in the modern world. Injustices to one country often has multiplier and chain effects of violence that extends to others not directly involved and that these multiplier and chain effects pose serious problems for international justice. Modern warfare, by its very nature, almost always includes significant innocents at risk whether they be just combatants, civilians of just nation, or civilians of even a non-attacked neutral country.