International relations (IR) scholars have increasingly integrated Hannah Arendt into their works. Her fierce critique of the conventional ideas of politics driven by rulership, enforcement, and violence has a particular resonance for theorists seeking to critically revisit the basic assumptions of IR scholarship. Arendt’s thinking, however, contains complexity and nuance that need careful treatment when extended beyond domestic politics. In particular, Arendt’s vision of free politics—characterized by the dualistic emphasis on agonistic action and institutional stability—raises two crucial issues that need further elaboration for IR research that appropriates her thinking. One involves the orientation of her international thoughts. Although Arendt shows “idealistic” aspirations for authentic politics practiced by diverse equals in an institutionally articulated space of freedom, she never loses interest in the extant situation of “non-idealistic” politics. Engaging with Arendt’s theory orientation requires a careful analysis of difficult topics, such as her distinctive conception of the political and her critiques of the nation-state and international law. The other topic that needs clarification when Arendt’s thoughts are applied to IR involves specific ways of associating different sites of power. A close examination of Arendt’s council-based federalism reveals her distinctive idea of international politics, based on her acute awareness of the fundamental complexity that lies in power association and state agency. Bringing IR topics like state agency into conversation with her works generates illuminating questions for Arendt scholarship. Likewise, the ongoing debate on agonistic and institutional features of Arendt’s thoughts can provide crucial insights into critical studies of international politics.