[hkmurakami]

I would imagine that the precedent the US would set with not honoring is defense agreement would have enormous repercussions for its relationship and bargaining power with both South Korea and Japan.

That would tip the balance towards US intervention.

[xiaoma]

If the US and NATO in general let Taiwan fall, it would pretty much guarantee Japan, Korea, Malaysia and Thailand to start nuclear programs.

[AnimalMuppet]

That's probably true. And if so, it means that it is probably not in China's interest to take Taiwan.