At What point is a national entity no longer that national entity? Let's take the famous example of Byzantines. The empire splits, one side dies, the other survives but with a different capital, language and culture.
It's like if USA annexed Mexico and then later on split into South USA and North USA. Capital of South USA is Mexico City and capital of North USA is Washington DC.
If North USA were to crumble into fragmented states, and South USA is the only USA left, is it really the continuation of USA if it's language is Spanish and it's capital is in Mexico City? Just because they call themselves American?
Romans died with Justinian
>>77711027
South USA would just be South USA, different from the original United States, but still connected to it, just like a son is connected to his parents. A son does not become the same as his father, a daughter does not become the same as her mother, but they were raised by them, so it's natural to find connections and similarities in the way they do things.
It also depends on how much influence had on South USA. if it was minimal, then it would be wrong to call themselves "americans"
>>77711027
American isn't a real nationality anyway