> https://en.wikipedia.org/wiki/United_States_Taiwan_Defense_C...

Taiwan existed because of the US. Basically, the other side of the civil war got defeated and come hiding in Taiwan behind US military. Otherwise, it'd have been invaded by China since.

It seems currently that there is no official military presence. However, there is this: https://en.wikipedia.org/wiki/Six_Assurances

I think it's enough to deter China from attacking Taiwan.