Maybe this is to simplistic but ...
When Mao's army of pheasants overran the mainland and the government of Chiang Kai-shek fled to the safe haven of Taiwan to pretend to still be the government of China, then that's when a line should have been drawn by the newly formed United nations.
Mainland is China under Mao, Taiwan is Taiwan under Chiang Kai-shek.
I guess there was so much else going on in those days.
Opportunity lost.
