Chapter 6 proceeds from a cosmopolitan perspective to address the problem of the crisis of the sovereignty of nation-states in the transition from the nineteenth to the twentieth century, to this end drawing on Hans Kelsen, who proceeded precisely from an awareness of that crisis to develop a monistic conception of international law relative to the states’ domestic law. In his analysis he called into question the very principles of nineteenth-century doctrine, where international law – conceived as the highest expression of the state – was accordingly reduced to what Hegel called external public law, or the state’s external law (äußere Staatsrecht). He instead drew on a tradition of thought that traced back to Christian Wolff and his doctrine of the civitas maxima, taking it up as the institutional form of a new society of peoples. Kelsen thus developed a conception that, moving beyond any contract-theory approach, made international law into a higher-order system independent of the will of the states. Corresponding to this doctrine was an ideology of “pacifism” set against the “imperialist” ideology of nation-states.