I originally wrote a long response, but it's gone so I'll keep it short: A. Siege type pressure when one lets food in (or food is passed in anyway) have extrem

I originally wrote a long response, but it's gone so I'll keep it short: A. Siege type pressure when one lets food in (or food is passed in anyway) have extremely poor success rate since WW2. Note that Yemen itself wasn't conquered (given the terrain and people, any idea of conquering it was laughable in the first place). Eventually PLA will either go Yemen, attack directly, or stop. All options are bad or worse than just attacking without trying a siege. B. SK and Japan will band if threat is deemed extreme enough. Or go nuke. C. The typically discussed invasion scenario is very tilted towards what American Marines did in WW2. A smart PLA would instead be far more aggressive on exploiting its air superiority, upto mobilizing sea assets after the air attack or even doing a Crete 1941 style attack. There are things Taiwan can do to defend, but it hasn't yet and I am not sure it's going to happen.