Within just the past few days, mainland China had overflown Taiwanese airspace some 103 times!
Taiwan should simply shoot down these Chines aircraft--either with or without the implied assistance of the US.
Or, at a bare minimum, Chen Chien-Jen should announce that the next time China acts so boldly, it will lose its aircraft--and then follow through on the threat. (Again, that is either with or without the aid of the US.)
I deeply dislike bullies--and that certainly includes countries that act in this manner.