Instead of 1997, suppose the lease that Great Britain signed on the New Territories of Hong Kong ran out in 1967 in the middle of the cold war. What would have happened? Would anyone honor the lease? Would the US have intervened to prevent a piece of the free world from being surrendered to the communists? One of the reasons the US was involved in Vietnam was supposedly to free the world from communism, right?
What if Great Britain didn’t sign a lease, but instead forced China to just cede it to them like they did before? What would have happened now? Would it evolve into another Taiwan situation? My guess is that the Chinese government would probably be more worried about their “rebels” over in Taiwan than to waste their energy on Hong Kong, and they would probably just leave it alone until Taiwan is taken care of. Any thought on this?
Don’t forget that Hong Kong itself was not subject to a lease - according to the treaty, Britain was obliged to return the New Territories on the Chinese mainland, but Hong Kong was ceded in perpetuity.
When discussions were held in the 80’s about the handover, it was noted that it would be futile to try and keep Hong Kong by force once the New Territories have been returned, as the fresh water plants that supply the island are located on the mainland. If the Chinese really wanted Hong Kong back enough to make an international incident out of it, all they would have to do is turn off the fresh water supply to the island, thus ensuring that the million-or-so inhabitants of Hong Kong Island soon begged to be handed over to the Chinese.
But to discuss the question on would Britain “forced China to just cede it to them like they did before?”: Hong Kong was originally captured to secure trade into China. In modern times, it was harming trade relations with China, so the natural course of action was to hand it back, resulting in the once-more lucrative trading agreements with this country. The fact that several million inhabitants of the free-est economy on earth were handed over to a communist regime apparently didn’t matter.
And as to what the US would think of this: well, I don’t think that the Chinese taking control of Hong Kong would be seen as a significant pushing back of the Communist borders, as Hong Kong is one small island on the coast of China. Besides, as mentioned above, it would be damned difficult (if not impossible) to defend.