That's what happened to Okinawa both by the Chinese, then the Japanese. America took it over after World War 2, but gave it to Japan in the 1970's. But, Japan had claimed "ownership" of it prior to that.
Okinawa used to be it's own country, so to speak, but it's so small, and resources so limited, they couldn't defend themselves from being taken over. The Japanese have even forbidden the Okinawan people from using their own language: they had to learn Japanese and abandon their own language called something like "Hogan", or "Hobogan"... I can't remember for sure.
The history here is really fascinating.
I haven't learned the language fluently, but I do know quite a bit of the history.
That's why we are here: the Japanese are not allowed to have a military other than for defensive purposes.
As much as the protesters protest our presence, Okinawa, and Japan as a whole would really be in dire straits without us here. We supply their economy tremendously here.
I really hope this remains a peaceful exchange, and does not turn ugly. 