How do religions and nationalism interact in secular democracies? With its history of nationalism based on religious ideologies, and the subsequent forced separation of state and religion, Japan provides a valuable case to examine how religion and nationalism interact and affect the politics of a secular state. The purpose of this dissertation is to understand and synthesize the divide within the literature regarding the idea that Shinto is fundamentally nationalist in nature. Due to Shinto's historical ties to Japanese nationalism, it is clear that religion and nationalism played a role in Japanese politics in the past. However, with Japan's transition to democracy and the constitutional provision of the separation between religion and state, religion's effect on nationalism in Japan has become blurred contemporarily. In order to explore these relationships between Shinto, nationalism, and Japanese politics, I investigate how political groups and religious organizations influence nationalist sentiment in political institutions and public opinion in Japan using the Japanese Value Orientations survey and an original dataset. I find that even though the evidence is mounting against the accuracy around the idea of State Shinto and the fundamentally nationalist nature of Shinto, the narrative persists. The existence of nationalist circles perpetuates these narratives, regardless of the truthfulness of the association between Shinto and nationalism because this narrative serves as a benefit to some groups. Shinto may not be automatically nationalist, but there are still nationalistic Shinto practitioners. The description of Shinto as inherently nationalist is not likely to go away while that description still serves a purpose.