Hong Kong was an interesting case. It was always part of China. GB effectively leased it for 100 years. GB wanted it as a harbor to be used for trade. It was GB that actually helped build what is there as it was basically wild lands when they moved in. When that lease was up, it reverted back to China. But in that 100 years, it had established its own legal system, currency, government, etc. So China couldn’t just suddenly put them back under Chinese rule without destroying the entire settlement. I would suspect that eventually China will establish some sort of agreement with the existing government in HK that they can continue to govern, but China will be the overall head on the horse. HK will end up in a situation like any of the 50 states in the US…they will have their own governance but will still have to work with the Chinese government on many issues.