At the end of the day, laws and authority are just a bunch of humans playing make believe with each other.
It all comes down to enforcement. Without enforcement, laws and authority are meaningless.
Take the USA and England as analogous to Taiwan and China.
In the 1700s, England had a "One-England policy" and claimed authority over the US colonies. The US colonies disagreed. Some of the international community acknowledged the One-England policy. Some didn't.
At the end of the day England tried to enforce their authority/laws and lost. Thus, England actually didn't have authority over the US colonies.
I suspect something similar may happen someday with Taiwan (though hopefully with less violence than the American Revolutionary War).
It all comes down to enforcement. Without enforcement, laws and authority are meaningless.
Take the USA and England as analogous to Taiwan and China.
In the 1700s, England had a "One-England policy" and claimed authority over the US colonies. The US colonies disagreed. Some of the international community acknowledged the One-England policy. Some didn't.
At the end of the day England tried to enforce their authority/laws and lost. Thus, England actually didn't have authority over the US colonies.
I suspect something similar may happen someday with Taiwan (though hopefully with less violence than the American Revolutionary War).