National differences and antagonism between peoples are daily more and more vanishing, owing to the development of the bourgeoisie, to freedom of commerce, to the world market, to uniformity in the mode of production and in the conditions of life corresponding thereto.So he admits that the engine of countries becoming friendlier to each other is actually the methods of the bourgeoisie, but fails to explain how removing those methods and replacing them with his, which are actually rooted in those that the bourgeoisie replaced (i.e. centralized authoritarianism with decentralized free-market republicanism), will actually make things friendlier between nations.
The supremacy of the proletariat will cause them to vanish still faster. United action, of the leading civilized countries at least, is one of the first conditions for the emancipation of the proletariat.
In proportion as the exploitation of one individual by another will also be put an end to, the exploitation of one nation by another will also be put an end to. In proportion as the antagonism between classes within the nation vanishes, the hostility of one nation to another will come to an end.