The China problem is a leftover from World War II, with the issues arising as the Republic of China (ROC) government occupied the nation after having accepted the surrender of the Japanese forces in Taiwan on behalf of the Allied forces.
In 1949, the ROC was overturned and replaced by the Chinese Communist Party (CCP). The People’s Republic of China (PRC) wanted to deal with what it saw as the remnants of China that remained outside of the PRC’s borders and the capture of the ROC has been its goal for well over half a century. It is this aim that is the basis of instability.