As I've mentioned before, what happens to Communism in China as its people are a exposed more and more to (the remnants of) capitalism? I'd say, first, China will reduce as an "economic powerhouse" (which I don't really believe it is, since all it does is assemble goods made elsewhere, tedious work that people will eventually reject), and then it will slowly ascend as a (semi-)free society.
If that happens, then all predictions (mine included) of China as a future enemy go out the window.*
*This post has way too many parentheticals. Sorry.