Rather, in the same manner that he defended the inevitability of progress in general (see my last essay), so he regarded perpetual peace as something that would eventually come about.
But as with all progress, perpetual peace would take a long time to develop, and much of it would be the of human action—the result of self-interested behavior that does not have international peace as its immediate purpose.
This condition will continue so long as there exists no international mechanism to adjudicate disagreements among states, so Kant called for a federation of states (one that would ideally include every state in the world) vested with the authority to resolve conflicts among sovereign states.
We should understand that Kant did not favor a world-state.
In his essay “Perpetual Peace (1795), Immanuel Kant continued a theme that he had discussed two years earlier in “On the Proverb: That May be True in Theory but it is of No Practical Use” (1793).
Kant had no patience with the claim—which remains common to this day—that philosophical principles have little if any relevance to the real world of practical actions.Ideally, a republican form of government is best suited to maintain peace.When the powers of government are separated into three branches—legislative, executive, and judicial—and when the supreme authority, the legislative branch, is elected by the people, then only this popular assembly will have the power to declare war.In the first paragraph of “Perpetual Peace” Kant made the following observation: The practical politician assumes the attitude of looking down with great self-satisfaction on the political theorist as a pedant whose empty ideas in no way threaten the security of the state, inasmuch as the state must proceed on empirical principles; so the theorist is allowed to play his game without interference from the worldly-wise statesman. Lewis Beck, in It would be an understatement to say that Kant did not subscribe to Plato’s doctrine of the philosopher-king.A typical ruler, corrupted by his desire to preserve and enhance his exercise of power, will never agree to have his judgment in matters of war overridden either by his own people or by other states.For now I will merely note my strong disagreement with this pernicious idea.Although many just-war philosophers, including Kant, had liberal tendencies and were motivated by a sincere desire to lessen the pretexts for war and to diminish its horrors, their treatment of states as sovereign moral entities generated enormous problems from a libertarian perspective.Like many classical liberals, for example, Kant invoked international free trade as a self-interested activity that, over time, will teach people the inestimable economic benefits of peaceful cooperation over war.Nations are less likely to wage war against other nations if those nations are mutually dependent on each other for essential goods and services.Like Grotius, Pufendorf and virtually every other just-war philosopher who preceded him, Kant viewed sovereign states as “moral persons” who exist in a state of nature vis-à-vis other states.As with humans who exist in a state of nature without a sovereign power to adjudicate disputes and enforce its decisions, a state of war will effectively exist among states.