Looks like we might have to defend them from Chinese aggression. We would have to get involved if China were to invade Taiwan or use some other tactic to harm their continued existence as a free, sovereign nation. But we couldn't do it alone. We would have to have backup, and even then it would be a scary operation. I hope there's a way to use diplomacy to solve the issue with Taiwan, but China is pretty stubborn on the issue. It doesn't look good.

The logistics of an invasion are beyond China's abilities.

The most likely response to any Chinese aggression towards Taiwan will most likely involve a blockade of ports along the east side of the country. That likely can be accomplished with the help of the U.K. and Australia. However, there are other countries that might be willing to get involved including from Vietnam, Japan, South Korea, the Philippines, Malaysia, and India.

Conflict with China would be economically devastating as well. You're right that a lot of other countries have a stake in making sure China's military doesn't become more menacing and decide to expand their territory. I hope that the threat of action from us and the other countries you mentioned is enough to keep them from looking for more land. It all depends on how sane their leaders are. I hope they don't get an unbalanced person to head their government like we did for the previous 4 years. That part of the world is a tinder box.