In the Project for Perpetual Peace in Europe, Charles-Irénée Castel de Saint-Pierre defies any critics of the European project by emphasizing the impact of an economic union on the prosperity of participating nations.
People have said that if the unifying treaty increases trade for France, Spain, Denmark, Portugal, and others, the improvement could only happen to the detriment of England and especially of Holland, who are currently the two greatest hubs of business of the Earth. Nevertheless, it is simple enough to respond to this particular objection, and demonstrate that improvement for some need not harm the commerce of others; the truth is that business will expand for all the nations, though it will expand proportionally for all. The twelfth nation belonging to the European economic community will increase its trade; but since all the others will also increase trade proportionally, it will remain only the twelfth trading party. That which alone composed a third of this trade, likewise augmented, will continue to be a third of the total. Thus, the nations best equipped for doing trade will retain the greatest portion of the business.
Charles-Irénée Castel de Saint-Pierre, Project for Perpetual Peace in Europe (1713).
Read the free text in the original language (1713 edition, volume I): http://gallica.bnf.fr/ark:/12148/bpt6k86492n?rk=21459;2
Read the free text in the original language (1713 edition, volume II): http://gallica.bnf.fr/ark:/12148/bpt6k864930?rk=42918;4