Kautsky

Very differently from the apprentice or the merchant is the modern
proletarian torn loose from the soil. He becomes a citizen of the
world; the whole world is his home.

No doubt this world-citizenship is a great hardship for the workers in
countries where the standard of living is high and the conditions of
labor are comparatively good. In such countries, naturally, immigration
will exceed emigration. As a result the laborers with the higher
standard of living will be hindered in their class-struggle by the influx of
those with a lower standard and less power of resistance.

Under certain circumstances this sort of competition, like that of the
capitalists, may lead to a new emphasis on national lines, a new hatred
of foreign workers on the part of the native born. But the conflict of
nationalities, which is perpetual among the capitalists, can be only
temporary among the proletarians. For sooner or later the workers will
discover that the immigration of cheap labor-power from the more
backward to the more advanced countries, is as inevitable a result
of the capitalist system as the introduction of machinery or the forcing
of women into industry.

In still another way does the labor movement of an advanced country
suffer under the influence of the backward conditions of other lands.
The high degree of exploitation endured by the proletariat of the
economically undeveloped nations becomes an excuse for the capitalists of the more
highly developed ones for opposing any movement in the direction of
higher wages or better conditions.

In more than one way, then, it is borne in upon the workers of each
nation that their success in the class-struggle is dependent on the
progress of the working-class of other nations. For a time this may turn
them against foreign workers, but finally they come to see that there is
only one effective means of removing the hindering influence of backward
nations: to do away with the backwardness itself. German workers have
every reason to co-operate with the Slavs and Italians in order that
these may secure higher wages and a shorter working-day; the English workers
have the same interest in relation to the Germans, and the Americans in
relation to Europeans in general.

The dependence of the proletariat of one land on that of another
leads inevitably to a joining of forces by the militant proletarians of
various lands.

The survivals of national seclusion and national hatred which the
proletariat took over from the bourgeoisie, disappear steadily. The
working-class is freeing itself from national prejudices. Working-men
learn more and more to see in the foreign laborer a fellow-fighter,
a comrade.

The strongest bonds of international solidarity, naturally, are
those which bind groups of proletarians, which, though of different
nationalities, have the same purposes and use the same methods to
accomplish them.
https://www.marxists.org/archive/kautsky/1892/erfurt/ch05.htm