Perpetual Peace: A Philosophical Sketch

Kant’s work is noteworthy for its blend of political and moral thought, and Perpetual Peace falls in line by asking what moral obligations fall upon states. Kant questions whether, if human beings are moral agents bound by the categorical imperative, if nations can themselves be held to the same universal law. Kant’s answer is yes, introducing his key theme of the moral obligation of states.

He begins from a simple but revolutionary premise: States are moral actors. Just as individuals are bound by moral law, states—composed of rational beings—must also act according to principles that could be universally willed. The categorical imperative is defined by acting only on maxims one would be comfortable with as universal law. Applied politically, this means that a state must never pursue policies that it could not rationally wish all others to adopt. For example, if one nation reserves the right to wage preemptive war, it must also accept the legitimacy of other nations doing the same. Kant sees this as an absurd and destructive contradiction.

Kant is sharply critical of the way states pursue their interests through war and deceit. His tone reveals this criticism, such as when he asserts that nations should not interfere with the constitutions of other nations: “For what can justify its doing so? Perhaps some offense that one nation’s subjects give to those of another? Instead, this should serve as a warning by providing an example of the great evil that a people falls into through its lawlessness” (4).