Both Presidents Chiang Kai-shek and Chiang Ching-kuo believed that there was only one China – the ROC – and both Taiwan and the mainland were part of the ROC. The ultimate goal of the KMT was to liberalize the mainland and achieve national unification. Therefore, the “one China” was clearly the ROC and Taiwan was part of the ROC.
At that time, Taipei denied the existence of the government in Beijing. Moreover, the ROC never believed its government ceased to exist; it simply moved from Nanjing to Taipei. Since then, Taiwan has existed without being part of the PRC for more than six decades.
Today, however, either under the KMT or the DPP, Taiwan no longer considers the liberalization of the mainland as a national goal. While the pro-independence DPP government has departed from the “one China” position and refused to endorse the “1992 Consensus” – one China with different interpretations; the pro-unification KMT has, generally speaking, acknowledged the “1992 Consensus” and dealt with the mainland on the basis of this consensus. Today considerable disagreement remains about what the concept of the ROC versus Taiwan would include. Some people in Taiwan define Taiwan only as the geographical region on the island of Taiwan and a few offshore islands. Others hold that Taiwan still include the geographical region of the Chinese mainland plus Outer Mongolia.
Zhimin Chen. Nationalism, Internationalism and Chinese Foreign Policy. Journal of Contemporary China, 14(42), 35-53.
Frank C.S. Liu and Francis L.F. Lee. 2013. “Country, National, and Pan-national Identification in Taiwan and Hong Kong”. Asian Survey, 53(6), 1112-34.