This is a little too... optimistic in my opinion. I dislike both nazis and commies, but it seems clear to me that there are deep and irreconcilable value and cultural conflicts at play in society. Ultimately, these groups do not "speak the same language of Good and Evil," as Nietzsche would say, and are potential precursors to new societies. They should be allowed to part ways, permanently, in my opinion.
Well, this world has formal boundaries we call borders. Beyond that, it's a big universe...
I know this sounds a bit glib, but I'm deadly serious about this. There are geopolitical complications, yes, as well as some additional complexity when it comes to commerce, but all in all, more regime diversity seems like a good path towards lessened internal social tension.