Fan, Hsin-HuaPopular sovereignty is a frequently used concept in contemporary politics. Many states, governments, or rulers claim to base their rule on popular sovereignty. Politicians use this concept often in their rhetoric. When people go to polls to cast their votes or go on street to demonstrate, they think they are exercising popular sovereignty. Popular sovereignty seems to be a well-recognized idea. However, in spite of its popularity, popular sovereignty often appears as an ambiguous notion. Could it be a myth or a fiction without much substance? Is it used only in political rhetoric, but has little objective reality? In his paper "The Very Idea of Popular Sovereignty: `We the People' Reconsidered," Christopher Morris does express skepticism about the possibility of attributing sovereignty to "the People". If democracy is understood as the rule by the People and for the People, then popular sovereignty is the foundation or essence of democracy. This implies that to understand and justify democracy, we have to understand and justify popular sovereignty. Or, if we cannot understand or justify popular sovereignty, then democracy would be problematic or impossible. Since democracy is increasingly deemed to be a universal value, clarifying and exploring its fundamental questions is not only unavoidable, but also important. An exact and thorough explication of the notion of popular sovereignty is therefore necessary. A skeptical view about popular sovereignty such as Morris's also needs to be reconsidered. Therefore, I aim to both construct and defend a theory of popular sovereignty. While providing an exact and thorough explication of popular sovereignty, I will also argue against skepticism about popular sovereignty. Specifically, there are three primary objectives in my theory: to clarify and reshape the notion of popular sovereignty; to discuss issues in realizing popular sovereignty; and to justify the People's right to sovereignty and explore the need for popular sovereignty. The general points I want to make in my theory are: the People in any state ought to be the sovereign; popular sovereignty can not only be understood, but also be exercised and realized.en-USDissertationPhilosophymajoritarianismpopular sovereigntyright to self-determinationsovereigntythe People