[Bigbluedot]

[size=11] compared to Taiw[/size]
Ukraine is about 17 times bigger than Taiwan. ... Taiwan is approximately 35,980 sq km, while Ukraine is approximately 603,550 sq km,
.......

How long can  usa defend taiwan is a question without involving in it directly.  It is a big question.

[Migrant]

It's up to China not US on Taiwan. 
Just block, US warship cannot enter. 
Not like Ukraine, it borders Poland. 
So there is an escape route. 
Taiwan once surrounded , it's over.