During the Republican era, the relationship between the individual, the state, and the world was a central theme in civics textbooks when presenting knowledge about diplomacy. Situated within the confluence of post-World War I idealism and escalating nationalism, these textbooks conceptualized individuals as “members of humanity” and sought to cultivate “world citizens” dedicated to human welfare, while grounding this vision in “national citizenship”. As the National Revolution swept across China and Nationalist Party ideological indoctrination intensified, the acquisition of knowledge concerning international affairs became integral to fostering “Three People’s Principles revolutionary citizens.” A qualified citizen possessing diplomatic knowledge was expected to be, foremost, a collective member capable of wielding the Three People’s Principles as ideological armor, demonstrating unwavering loyalty to Nationalist Party doctrine, and maintaining strict adherence to leadership and discipline. While civics textbooks explained “diplomacy” to the public, they also utilized the production and dissemination of diplomatic knowledge to shape domestic society. This dual function illuminates both the international dimensions of Republican-era civic education and demonstrates the domestic political utility of “diplomacy” as both educational resource and knowledge apparatus.