The May Fourth Movement happened one hundred years ago. The century between 1919 and 2019 was not only the critical epoch of China's transformation from an empirical to a republican order, but also a turbulent time during which China explored its modern political institutions. This article first illuminates the significances of the May Fourth Movement in the history of modern China-as a patriotic student movement, a new culture movement, and the precursor of Marxism-Leninism in China. It then examines the processes of democratization in Mainland China and Taiwan, as well as the relative merits and shortcomings of "people's democracy" and "constitutional democracy." Finally, this article reflects on the significance of institutional competition between the two sides of the Taiwan Strait, and asks questions regarding the universal value of democracy.