The state is the central actor in both political science and political history. As Richard Evans argues, history as a university subject … was traditionally ‘emphatically the political history of the nation-state and its relations with other nationstates. The history of high politics and international diplomacy was king’ (Evans, 1997a: 161). Knowledge of sovereignty, as both a political attribute and a legal status of the state, is not only vital to a thorough understanding of state behavior in IR, but key to appreciating the driving force of much European and international history. The problem is that sovereignty itself encapsulates both political and legal facets. While much can be said (as evidenced by the Introduction) for using international history to obtain a deeper appreciation of international relations, law itself presents a very different perspective of the international system. As Charles De Visscher argued in the 1950s, international law is not an easy fi t in explaining the imperatives of IR:

There is no branch of law that lends itself less easily than international law to this reduction to a system of the mere imperatives of abstract logic. The dangers of schematic conceptualism are never more apparent than when it is applied to relations where particular situations are far more important than general situations and where, consequently, general norms are still far from occupying the place that belongs to them in the internal order.