One of these days I hope to write a series on the theory of war.
If I manage to follow through on this plan, I will criticize in detail the notion that we should view states as moral persons, analogous to morally autonomous human beings existing in a state of nature.
Rulers will usually follow the dictates of prudence—where “prudence” means actions that will advance the interests of the rulers themselves—rather than respect the universal laws of justice, as demanded by the Categorical Imperative.
Meanwhile, rulers will contemptuously dismiss those philosophers who argue that the principles of justice should be upheld in the arena of international relationships.
By a “state of war” Kant did not mean continuous violent conflict but rather the continuous of such conflict.
Each state will naturally fear other states, and this fear will often result in war.
This is a moral imperative, for the same reason that governments are necessary to preserve domestic peace.
A state of war will exist, whether nationally or internationally, until and unless individual moral persons, including sovereign states, submit to the binding resolutions of an overarching authority.
Kant regarded this belief as especially pernicious in the realm of politics, as when politicians claim that moral principles cannot realistically be applied to the ruthless and frequently violent interactions between sovereign nation-states.
Rulers will almost always seek to preserve their own power, even if this entails committing serious injustices against innocent people, both domestic and foreign, through aggressive and predatory wars.