Commerce and industry, traffic in books and letters, the commonality of all higher culture, quick changes of locality and landscape, the present-day nomadic life of all nonlandowners - these conditions necessarily bring about a weakening and ultimately a destruction of nations, or at least of European nations, so that a mixed race, that of the European man, has to originate out of all of them, as the result of continual crossbreeding. The isolation of nations due to engendered national hostilities now works against this goal, consciously or unconsciously, but the mixing process goes on slowly, nevertheless, despite those intermittent countercurrents; this artificial nationalism, by the way, is as dangerous as artificial Catholicism was, for it is in essence a forcible state of emergency and martial law, imposed by the few on the many, and requiring cunning, lies, and force to remain respectable. It is not the self-interest of the many (the people), as one would have it, that urges this nationalism, but primarily the self-interest of certain royal dynasties, as well as that of certain commercial and social classes; once a man has understood this, he should be undaunted in presenting himself as a good European, and should work actively on the merging of nations.
Friedrich Nietzsche, Menschliches, Allzumenschliches (1878), section 475
(Human, All Too Human, trans. Marion Faber and Stephen Lehmann)