Introduction The continued primacy of the sovereign state as the principal actor in international relations constitutes one of the most enduring structural features of global politics, despite recurrent predictions of its erosion in the face of globalization, transnational networks, supranational governance, and non-state actors. From the Treaty of Westphalia (1648) to the contemporary multipolar order, … Continue reading What structural and historical factors explain the continued primacy of the sovereign state as the principal actor in international relations? Contrast realist, liberal, and constructivist explanations of state primacy in international relations.