Immanuel Kant’s cosmopolitan constructivism unfolds from the role that the right to visit plays in linking republican states and peoples among themselves into a cosmopolitan constitution. The cosmopolitan right to visit arises from the move from the possessio phaenomenon in unilateral external acquisitions to peremptory possession according to public right. For Kant the notion of cosmopolitanism embraces two dimensions: one concerning the general international order that is required for perpetual peace and the other concerning the cosmopolitan right in a strict sense, that is, the third section of public right. The idea of a cosmopolitan constitution reflects a process of progressive constitutionalization of international law, starting from the adoption of a domestic ‘civil constitution’ and then converging towards an incipient trans-national arrangement identifying peremptory norms. Due to the limited size of the Earth, territorial exclusion is omnilaterally acceptable only if state authority is held under an obligation to allocate a cosmopolitan compensatory measure.