I have seen something of the project of M. de St. Pierre, for maintaining a perpetual peace in Europe. I am reminded of a device in a cemetery, with the words: Pax perpetua; for the dead do not fight any longer: but the living are of another humor; and the most powerful do not respect tribunals at all.

Letter 11 to Grimarest: Passages Concerning the Abbe de St. Pierre's 'Project for Perpetual Peace' (June 1712). Taken from Leibniz: Political Writings (2nd Edition, 1988), Edited by Patrick Riley.