Protestantism is essential in US history and politics and predominantly affects how the American government and people behave. This paper focuses on how Protestant theology and churches affect the politics of the US by discussing the historical background of some denominations in America, the elitism in politics from church traditions, and the dual influence of Protestantism on democracy. Using literature research methodology, the paper concluded that Protestant Christianity, especially the Reformed church, has a considerable impact on US education, politics, and democracy that anyone who wants to analyze American politics cannot ignore. Also, the work ethic derived from Protestantism suggests that Protestant values have contributed to the development of capitalism and industrialization in the United States. Meanwhile, the research of different denominations can help people understand seperation of some states and parties. The research paper provides a perspective for readers to consider America a religiously affected country that cultures and policies are nearly all under Christian influences.