Zenan Li welcomes Sully Sullivan, Teaching Fellow at Harvard University, for an engaging discussion on the foundations and future of international relations. Sully shares his journey into the field, his teaching philosophy, and the theoretical lenses—realism, liberalism, constructivism—that he finds most illuminating. They unpack evolving global power dynamics, the role of alliances and institutions, and the impact of digital technologies and AI on diplomacy. Sully closes with practical advice for aspiring IR students and scholars looking to make a meaningful impact.