Losing self-confidence and direction in multiple aspects for failure to find a way out after trying every approach，given adherence to fundamental institutions，against predicaments in governance，the United States stepped into a lost age which become increasingly fierce in 2023. Politically，conventional beliefs in constitutionalism and rule of law are challenged by conspiracy theories and judicial politicization；beliefs in democracy are challenged by Uncompromising politics，generational shift and the difficulty of voters’ choice；beliefs in the advantages of federalism are challenged by executive power contention，legislative power contention，and interstate rivalry；beliefs in U.S. international hegemony are challenged by anxieties about its hegemonic status and declining effectiveness of the alliance systems. Economically，beliefs in the market-led model of capitalism are challenged by Bidenomics and regulatory policies；beliefs in the effectiveness of the U.S. macroeconomic systems are challenged by the difficulties of the financial system and the fiscal system. Socially，beliefs in the “City on a Hill” are challenged by ethical scandals，public safety deterioration，and intensified social stratification；beliefs in “post-ethnic” national development are challenged by ratio changes in national composition and intensification in ethnic conflicts. The preeminent reason for U.S. to enter a lost age is the excessive economic change，which causes additional excessive multifaceted social changes through existing political and social mechanisms，which is seriously deviated from traditional beliefs. Getting out of the lost age requires good economic and social fundamentals，achieved through economic development or political compromise，to bring reality and faith back together.