The end of the twentieth century saw the temporary decline in the importance of the concepts “sovereignty” and “nation-state.” As the hopes for a cosmopolitan post-national world unraveled, “sovereignty” and “nation-state” were deemed to be outdated and obsolete for at least two reasons. On the one hand, globalization and internationalization have allegedly transformed the Westphalian world order of independent sovereign states, bringing about a future of post-state cosmopolitan universalism. Sovereignty, a concept co-original with the statist imaginary, was believed to be destined to wither away together with the nation-state. On the other hand, sovereignty was targeted for its incompatibility with the principles of constitutionalism and the rule of law. Perhaps, sovereignty, understood as the highest absolute indivisible power, was fit for the old regime of contesting nation-states. However, it was claimed, it is alien to contemporary constitutionalism with its core principles of separation of powers, constitutional limitations, and international cooperation.