An important debate in International Relations and International Law is whether states are persons. In this article, it is argued that they are. That is, they are real persons-as-status. Furthermore, state personhood is argued to be an ideological category, marked by ideological variety. Roughly, one can tell apart liberal and republican conceptions of state citizenship. In a case study, the conceptual toolkit of state citizenship is put to work to assess the liberal credentials of modern international society. While modern international society rests on firm liberal principles, expressed most clearly in the Charter of the UN, important republican elements can be discerned, not in the least in the constitution of NATO.