"[A] political equilibrium is neither a gift of the gods nor an inherently stable condition. It results from the active intervention of man, from the operation of political forces. States cannot afford to wait passively for the happy time when a miraculously achieved balance of power will bring peace and security. If they wish to survive, they must be willing to go to war to preserve a balance against the growing hegemonic power of the period."
January 1, 1970
https://en.wikiquote.org/wiki/Nicholas_J._Spykman