Not quite the same, as Taiwan wouldn't even exist as a separate entity in any shape or form without the Americans' generous assistance in 1949, when Maos' shoeless and weaponless people's army conquered the mainland.
In Ukraine, the borders are those drawn by the USSR, have absolutely no historical or other (treaty) justification.
The Western part was Polish for centuries up until the end of WWII; Trans-Carpathia was Hungarian for about a 1,000 years, then part of Czechoslovakia after WWI, only to be chopped off and incorporated into the USSR in 1945.
Take all these areas away and you won't have much left outside Kiev.