So what should the US do in the event that China, for whatever reason, decides to force the issue with Taiwan?
Depending on when this happens LA would be one of the most likely targets for a nuke if it escalates to the civilian target level, and obviously i wouldn't want to volunteer for such a thing. However i'm not sure if that's sufficient grounds for backing down. I'm not a big fan of the domino theory, but if we don't defend Taiwan against Chinese aggression, what do we do if they decide they want Japan? Or Hawaii?
I think we have a right to help defend anyone who actually _wants_ our help. I'm not sure who we have a duty to defend though. If we _knew_ that China would be happy after taking Taiwan and thereby restoring its "natural" borders, would it be worth fighting on the side of the Taiwanese who don't want to be "restored?" What if we _knew_ that China would nuke a couple of US cities of we intervened. Is that sufficient reason to tell Taiwan to sink or swim on its own?
And if we do decide to support Taiwan, how far should we be willing to go with that support?
The best guess i've heard as to what would happen if China did use nukes is that they'd start out hitting a US Carrier battle group with a tactical nuke, and after that it would depend on what response the US decided to make.
Letting China nuke a Carrier battle group and then doing nothing about it would be even worse than just letting China have Taiwan, but how _should_ we respond in such a situation? According to people discussing this on a mailing list i'm on, US doctrine is that in the event of an attack by WMDs, the US will respond with its own WMDs, which makes sense in light of the whole MAD thing. However the question of proportion would remain. Do we nuke a Chinese CBG or three in response and then see how they respond to that? They might give up at that point, or they might decide to escalate and nuke more military targets, or start ending missiles across the Pacific to nuke civilian targets over here.
We could respond by nuking every military target we know of, but that would involve laying waste to, well, pretty much all of China's coast with huge civilian casualties. Is it worth going to that extent to (try and) make sure that we don't get nuked? And taking a step back, is it worth going to that extent to (try and) make sure that Taiwan isn't conquered?
And on top of all that there's always the fact that backing down due to a threat of force tends to set a bad precedent, but that leads back into the domino theory.
Many people argue that rationally China doesn't want a full scale war with the US, so the best policy is to make damn sure that China knows that's what will result if they make any military moves against Taiwan. Of course that involves a certain amount of saber rattling which isn't exactly great but certainly beats some of the alternatives.
There's the relative freedom of some 20 million Taiwanese at stake, the safety of between ten thousand and a hundred or so million americans at stake, and in the worst possible scenario, the safety of possibly upwards of a half billion chinese at stake, a great number of which may not give a damn at all about what the Chinese government wants to do with Taiwan (i have no idea how nationalistic the average chinese citizen is.)