Viewpoints Within Taiwan
Within Taiwan, there is a distinction between the positions of the Kuomintang (KMT) : the Kuomintang also believes in the "One China Principle" and maintains its claim that under the ROC Constitution (passed by the Kuomintang government in 1947 in Nanjing) the ROC has sovereignty over most of China (including by their interpretation both mainland China and Taiwan) and, according to some interpretations of that constitution, Mongolia.
The Democratic Progressive Party does not agree with the "One China principle" as defined by the KMT or Two Chinas. Instead, it has a different interpretation of this principle and believes "China" only refers to People's Republic of China and states that Taiwan and China are two separate countries, therefore there is One Country on Each Side and "one China, one Taiwan". The DPP's position is that the people of Taiwan have the right to self-determination without outside coercion
With the liberalization of the Three Links, enabling people on Taiwan to visit mainland China, the One China idea was reinforced by some returning Taiwanese intellectuals who concluded that, "in so many basic ways, their culture is the same as the one on the other side of the Strait". Taiwanese businessmen with business operations in mainland China are also a major constituency for the one China principle.
Read more about this topic: One-China Policy