Disclaimer: this is a relatively informal piece of writing where I am exploring some ideas relating to war and pacifism, me being a pacifist. I plan on writing a more organized piece with more depth and attention to the relevant literature in the future. But for now, enjoy!
In writing about contingent pacifism, and the concessions I must make for the pragmatism of pure pacifism in respect to revolution, I made it clear that I do not believe that revolution can be justified in the modern day. However, the open-ended nature of my conclusions may lead some to think that war itself might be justified. This seems clear if you take the assumption that some revolutions are justified, and revolutions are typically war (i.e., revolutionary war of 1776, Haitian revolution, etc.). This, however, is not true, as war as a concept is different from isolated revolution. In a time of symmetrical warfare, where the weapon that you are using to enact violence may only act singularly towards a target that you can more carefully control the intentionality of, perhaps a defensive war could be viewed as justified. Thus, it would be accurate to say that there was a time in history in which I would agree with the statement that some wars can be justified. But with the invention of the automatic weapon, and even the semi-automatic weapon, the prospect of a just war died with the hundreds and thousands of lives lost at the end of a barrel. As a result, I do not believe that any war conducted today can be justified without an absurd level of attention paid to controlling the effects of said war.
Although I will concede that defensive wars, such as that fought by the present-day Ukrainians against Russian invasion, are more permissible, the standards by which the permissibility of the defensive action is assessed are based directly upon the directness of the threat that you are defending against. If, for instance, Russia were to invade Poland, and World War against all of the NATO member nations were to occur, I do not feel that it is ethical for a country unrelated to this direct exchange to join in the defensive action. Defensive pacts muddy the waters, as the countries have, in effect, entered a social contract with the country that has been invaded, and this becomes even more complex when the aggressor is the country with whom you have a defensive pact. I ultimately believe that this is still an immoral action, even if it is not as immoral as if you were actively defending yourself from invasion. Thus, an American soldier fighting in Ukraine as a result of the Russian invasion is an immoral action, as it is aggression outside of self-defense. Similarly, if Russia were to threaten American allies, it would still be immoral for an American to defend those allies, if not as immoral as if they were to independently aggress against Russians. Here, we see a direct contradiction within the social contract of countries and the social contract of moral expectation. It is illustrated as follows:
1) As per a previous paper regarding contingent pacifism, we operate under a contract of non-aggression. If someone does not aggress against us, we do not aggress upon them.
2) You have entered into a social contract with another country such that you must defend them from aggression or join in a conflict that they have joined as per the terms of said contract.
Due to this contradiction, the justification of the act of joining the war is once again muddied. One could argue that it is dependent upon whether the party for whom you would be entering war has themselves violated a social contract, but I do not believe this is sufficient, as it is predicated on the notion that there ought to be an international police or justice enforcement organization that has the authority to punish nations that operate outside of the contract. This might be attractive, but as there does not currently exist a universal model under which this has been set (the closest being the UN, but this is incomplete as an enforcement measure, lacking the logistical frameworks under which this enforcement can be made, beyond sanctions). There has been past indication that the United States would take up the role of the "international police force" of nations, but I do not feel that this is right, as it enforces American ideals and values upon other nations regardless of their desire to have these values enforced. This, in effect, attempts to form a one-sided contract that, if not followed, results in violent retribution, and I am not in favor of this. As a result, even if we state that a country like Russia has violated the social contract by invading Ukraine, we cannot say that this justifies direct involvement in the conflict, as the United States is not, and should not be, the enforcement arm of the UN.
So, if we cannot remove the moral consideration of a nation if their leaders have violated the contract of non-aggression, how do we cope with the contradiction in rules? I feel that what should take precedence is the contract of superior value or importance. To explain, I will give a thought experiment:
Suppose that there are two men who have entered a contract with each other wherein one man gives all of his money to the other in exchange for a cookie that the man was making. Now suppose that the man who is giving the money is substantially intellectually disabled, and does not understand the value of money, nor the value of the cookie as it relates to the money that he is giving. Is it justified to void the contract because the contract itself violates the primary set of rules under which the foundational contract of autonomy is set? I feel that it is, as the contract was set in violation of primary rules, thus meaning the contract was never valid to begin with.
Applied to a defensive pact: if one forms a defensive pact under which the conditions of the pact are such that aggressive action might be taken that violates the rules of contingent pacifism, then the contract itself is void, and thus no contraction exists.
In other words, there is no way to engage in modern warfare that is ethical short of pure defensive action wherein your direct safety is at risk. This is an important distinction, as I feel that the EU agreeing to defend member nations if they are invaded by Russia is defensive, as Russia would represent an immediate threat beyond the borders of the nation they are invading due to past actions made by the Russian state that indicate their likely motivations. In particular, former members of the USSR who are a part of the EU or NATO would, in particular, be justified in defensive action towards their fellow EU and NATO members in defense against Russia. The United States, however, would not be justified, as it is not in danger in this invasion scenario. If substantial human rights abuses (such as the genocide of the Jews during the Shoah) are taking place in Russia, this might complicate matters, but as they are not (as far as I am aware—correct me if I'm wrong), this does not matter here.
Thus, the conditions under which a war can be justified are so limited that it is unlikely for any war, particularly any war acted out by the United States, to ever be justified. If America is invaded, or Canada were to be invaded, this might change, but as it stands, neither are likely to be invaded, and thus a just war from the United States is exceptionally unlikely, if not impossible.