Hong Kong and Mainland China have pretty much completely separate political systems except for military and foreign affairs. I think this is supposed to last another 40 years or so at the minimum.

It's weird how two regions connected by a subway system can be so different from one another, and yet still be the same country. My wife is a Chinese citizen but needs a visa to go to Hong Kong... as an American I don't but I need a visa to go to mainland PRC. Fun!