Emotion? Maybe. But controlled emotion. The Chinese psyche is ineffected with concepts of sovereignty; much more so than your average right-wing, black helicopter-seeing, militia guy in the US. It comes from their "century of humiliation" when they were taken advantage of by western powers. Whether we agree with that characterization is irrelevant, it's what they believe. Thus, they will take whatever action necessary to preserve their sovereignty. Since they see Taiwan as part of China (and they have a pretty good legal argument), this naturally fits within their sovereignty plans. They don't need to go toe-to-toe with us in an effort to win. They simply need to make it too costly for us to fight and that's looking much easier these days. Would most Americans really support spilling American blood to protect Taiwan? As the father of a kid who could be doing the fighting in as little as ten years, I'd say NO.

That being said, the real issue isn't really Taiwan. Assuming complete compliance with international law in all respects, would our world really change if Taiwan decided tomorrow to join China? However, I think our world would change greatly if access to that part of the world was suddenly denied. Half of world maritime trade transits that part of the world. This short paper, although dated, gives a good idea of the issue. I'm really only beginning to explore the economic nexus here, but I see the potential impact as perhaps catastrophic. China seems to be pursuing an anit-access/are denial (A2/AD) strategy that, if successful, poses are far larger threat than AQ and their ilk. This A2/AD strategy employs military, political, legal, and media means. Sure, the Air Force uses this to strike up fears to drive their share of the budget, but there is still a concern here that should be address and I think we've ignored this for too long because of our other committments.