This chapter will explain why and how the KMT's one-party rule was established in Taiwan following the end of Japanese colonial rule. Despite its anti-communist stance, a one-party rule was established in Taiwan. The KMT aimed for democracy and sought legitimacy through the implementation of “constitutional government.” However, the transition to constitutional government during the civil war between the KMT and the CCP gave rise to a new form of dictatorship known as the “tripartite coalition dictatorship.” Confronted with the unprecedented crisis of defeat in the civil war and the loss of territory, the regime in Taiwan was restructured to strengthen dictatorship as a means for survival, leading to the establishment of the KMT's one-party dictatorship in the 1950s. For the KMT government, which effectively governed only Taiwan, the importance of maintaining the “legal legitimacy” of the Republic of China as the government representing all of China increased significantly. Although Chiang Kai-shek’s personal rule was intensified, his authority was limited by the dual constraints of constitutional government and legal legitimacy, ensuring that the dictatorship remained within the framework of party rule.