There's a great quote in Asia's Cauldron where Kaplan is talking to some Vietnamese general about how amazingly friendly everyone is to him, even though he's an American. The general says (paraphrasing) "but Mr. Kaplan - Vietnam only went to war with you once! We've been at war with China for a thousand years and they're our largest trading partner!"
China has just enough WMD to convince you not to fuck with them. I also doubt they've got anything resembling the readiness of the American arsenal. But it won't come to that - they've got a piece on the big board which means they get to play Diplomacy for Grownups and they didn't even need to buy a whole Strategic Air Command. Anybody with any sense knows that you don't practice anything other than asymmetrical warfare if you want to be a world power - which is why the Chinese have focused their defenses on making US operations in the pacific theater unsafe, not unthinkable. All they have to do is arrange for the least disruptive move to be letting them snake Taiwan and control the China Sea and they're pretty much good.