Taiwan represents the one US ally who fought the Japanese in China effectively.  Mao ran and hid in the north with the Long Retreat, oh i mean Long March.  He laid low all through the war and waited for Chiang Kai-shek to do all the heavy lifting during the war.  With Chiang's forces exhausted from decades of war and freshly supplied with Soviet weapons, all rested up from hiding out for the past 8 years, Mao swept southward and to everyone's surprise conquored China.  But the US long admired Chiang, and especially Madam Chiang with her soft southern accented English, and since he stood by the US and fought the Japanese bravely, the US has always returned the favor and stood by the Taiwanese as they represent the last vestige of Chiang's government.  Anyone who thinks he US would abandon Taiwan is in for a big surprise and one hopes the thugs in the CCP do not make that mistake.