'Unions' is of course plural, so when Nietzsche writes of the need for "international racial unions", he is not talking of one union, but of many!Nietzsche does not think that ALL these race unions will produce ONLY Supermen! No doubt this is the egalitarian fantasy of those who wish to pervert Nietzsche, so that they can say "we're all Supermen now"!

Wrong;

Nietzsche advocates an Aristocracy built on a steep Order of Rank, beginning in the Slavery of the many, and ascending to the Supermanhood of the Few.Some of these international racial unions will produce only under-men, sub-men, last men; men as instruments, and men as slaves; only a Few of the Race Unions will be able to produce Higher men and Overmen!

The reason for "international" Racial Unions is because the races have become spread out internationally. The White Race is now scattered across the globe; therefore, something like Rockwell's 'White Power' is a nascent International Race Union. Indeed, this is the meaning of the World Union of National Socilaists.Similar movements in other Races are afoot (e.g., Black Muslims).Of course, as I said, some Race Unions will produce material only for the lower echelons of the Order of Rank (and some will be exterminated).