No, the ROC on Taiwan is a government-in-exile. Any past diplomatic relations with the ROC on Taiwan in that condition made it a foreign policy instrument of the USA. It was solely on the basis of being the legitimate government of China. It was the anti-communist intention of the US Secretary of State Dulles to restore the ROC government-in-exile to the China mainland. However, this failed and the ROC on Taiwan remained the Chinese military governors or US recognized rebel belligerents on Taiwan. This recognition condition was a legal duality of the ROC on Taiwan and the sponsorship by the USA. It also raises some banned practices of using of a puppet government or proxy occupation of Taiwan. However, it seems “rebel belligerents” is how John Dulles has avoided this potential proxy occupational issue of the Hague Regulations. It is allowable. 
Were East Germans citizens of West Germany? No. But the political status of West Berliners was an issue even the US Court of Berlin did not want to probe too deeply. West Berlin was a German territory under American occupation. But it was not a sovereign part of either West Germany or East Germany under the Bonn Convention of 1955. It still remained apart of the “One Germany” which was officially reunited in 1990. We just simply delegated the temporary administrative functions to the West Germans and applied German Law from 1871. This was based upon a customary practice of occupation which keeps current territorial laws in force until the occupier alters them. So we just never really altered anything “German” under customary law of war from 1945 and beyond. West Berliners were German nationals of their Germany territory held under the customary laws of war and Law of Occupation. But they weren’t exactly the citizens of West Germany by the Bonn Convention.
So by customary laws are you “Chinese” of the China mainland or “Taiwanese” of the Taiwan territory in SFPT? Read Art. 5 of the 1895 Treaty of Shimonoseki and you will clearly see customary law of a “territorial nationality” as it is put into effect for two years.
The ROC laws on Mainland Relations between the Taiwan Area and Mainland Area really reflect the practices of West Berlin. It is a modification of the customary laws of war in SFPT.
The October 25, 1945, ‘Retrocession Day’ formalities were bungled by Chen Yi and so Chinese are colluding to “steal” Taiwan. George Kerr wrote on this in “Formosa Betrayed”.
You may not realize that he was a Civil Affairs Officer in the US Navy during WWII. (Since 1955-today, however, the civil affairs issues are handled by the US Army.) He fought for years to protect the Formosans but the ROC just kept accusing him of protecting Japanese nationals. Formosans were Japanese nationals until April 28, 1952, and this is still recognized in many Japanese Court cases. Retrocession Day is null and void because it just marks the beginning of joint-occupation of Japanese territory. On that day, the US Military Government had started the official period of “enemy occupation” of Japan. This is critical.
The ROC just gave up their claims to China mainland in 1991 when Lee Tenghui came into power. There is still the Taiwan Area of the ROC Constitution which is rooted in occupational government on Taiwan.
Kissenger did make the first substantial changes in 1971-72.
It resulted in the signing of the Shanghai Communique on February 28, 1972. Based upon some inferences of some declassified documents, Kissenger knew the significance of February 28, 1947, to the Taiwan independence movement.
This symbolism has disturbed me as we know the great emphasis Zhou Enlai would have placed on something like that.
No. President Nixon was very emphatic in his directions to Dr. Kissenger and General Alexander Haig. Do not violate the treaty obligations to Taiwan. Both the SFPT and Mutual Defense Treaty were in effect at that time.
MDT was terminated in 1979 because advisors to President Carter had delusions of granduer for causing the diplomatic switch and the signing of their second Shanghai Communique. When Carter officially derecognized the juridical person of the ROC government-in-exile on the basis of being the lawful government of China, he also stopped the sponsorship and American use of the ROC as a foreign policy instrument.
Art. 6 of the MDT was constructed in a perculiar manner of territorial overlap and the 1955 MDT “Exchanges of Notes” between Dulles and George Yeh of the ROC puts some great emphasis on this unique aspect of the SFPT role in the MDT. There is jurisdictional duality of SFPT in the MDT and Carter terminated it in 1979. Senator Berry Goldwater challenged this MDT termination all the way to the Supreme Court. In Goldwater v. Carter, the US Supreme Court clearly states it has not examined these treaty termination actions of the Commander-in-Chief. The military issue is wide open to being revisited. Goldwater dropped the MDT issue because they created the Taiwan Relations Act. Again, the SFPT is intertwined with the defense issues of Taiwan as it was with MDT.
During the Carter rush to create a legacy, Secretary Richard Holbrooke got into a fistfight with the Secretary for Human Rights over the Taiwan rights issues. The “human rights” clause of the TRA is really directly attributable to Holbrooke when the drafters in Congress added it. It seems that under the customary law of war, there are issues of “undefined” civil rights in a landmark supreme court case in 1900. There are “human rights” for cessions of peace treaties during any temporary miliatary occupation. The “human rights” clause of TRA is not even window dressing, it is a legally veiled threat from Congress to Richard Holbrooke and his “Fourth Communiques”. Congress has promised undefined civil rights enhancements to you and the people of Taiwan for things like self-determination. There are legal issues of SFPT for “undefined” civil rights under the treaty clause of TRA. 