Every nation on earth acknowledges that Taiwan belongs to China. This includes the United States! Just look at U.S. Relations With Taiwan (dated May 28, 2022):
The United States has a longstanding one China policy,…we do not support Taiwan independence;
From the Shanghai Communiqué:
The United States acknowledges that all Chinese on either side of the Taiwan Strait maintain there is but one China and that Taiwan is a part of China. The United States Government does not challenge that position.
The Government of the United States of America acknowledges the Chinese position that there is but one China and Taiwan is part of China.
From the Joint Communiqué on Arms Sales to Taiwan:
The United States Government attaches great importance to its relations with China, and reiterates that it has no intention of infringing on Chinese sovereignty and territorial integrity, or interfering in China’s internal affairs, or pursuing a policy of “two Chinas” or “one China, one Taiwan.”
Today, in 2022, the United States can no longer exert its hegemonic influence over the China-Taiwan situation. China is too big and powerful.
No nation believes Taiwan is an independent country, not even Taiwan itself! Just look at Taiwan’s constitution. It clearly indicates that Taiwan is the “free area” of ROC, meaning that mainland China is the non-free area. Taiwan has never, ever, declared independence.
The fact that Taiwan is self-governed does not imbue it with nationhood or sovereignty. The best counter-examples are Hong Kong and Macau. Nationhood is solely a matter of international recognition, and thus I remind you of the previous two points.
There are no laws that govern what constitutes nationhood. There is no mechanism of adjudication for nationhood. It really and truly is a matter of international recognition.
Taiwan has been part of China since the 1600s. It was stolen by the Japanese in 1895 but was returned to ROC after WWII. When ROC lost the civil war in 1949, PRC inherited Taiwan.
From the Cairo Communiqué:
…all the territories Japan has stolen from the Chinese, such as Manchuria, Formosa, and The Pescadores, shall be restored to the Republic of China.
The civil war is unfinished. No treaty has ever been signed. This means that the two sides are still one country!
China is China, and has always been China, regardless of who ruled it. China was China under dozens of dynasties. China was China under ROC. China is China under PRC.
So any argument about PRC not controlling Taiwan is irrelevant.
#1: The China-Taiwan situation is China’s domestic matter or internal affair. It’s nobody else’s business.
#2: China will no longer tolerate interference in their domestic matter. Why should she? Would USA or Canada tolerate similar interference from China?
#3: Interference will lead to devastating war. Why then should we intervene? What’s our justification?
And is it worth it?