ABSTRACT
As has been indicated elsewhere, a consistent theme in international society in the last 100 years has been the need for states to work together to achieve common objectives and, to a large extent, this need explains the proliferation of international and regional organisations. However, in the 19th century, the traditional view was that only states were legal persons in international law. Writing in 1912, in the second edition of his celebrated treatise, Lassa Oppenheim could note: ‘Since the law of nations is based on the common consent of individual States, and not of individual human beings, States solely and exclusively are subjects of international law.’1 In broad terms, states remain the principal legal persons on the international stage, but the presence of international and regional bodies has transformed the picture considerably. It should not be thought that this development stems directly from 1919; there is evidence of international co-operation in the 19th century in bodies such as the Commission for the Rhine (1815), the Elbe (1821), or the Po (1849) and, towards the end of that century, it had become clear that co-operation on technical matters was unavoidable as instanced by the establishment of bodies such as the Universal Postal Union (1874). Indeed, after the Congress of Vienna (1815), Metternich had tried to manage European affairs by regular diplomatic conferences and these continued after his fall, as instanced by the Paris Conference of 1856 on the Balkans and the Berlin Conferences of 1878 and 1884-85. Thus, prior to 1914, European peace depended on periodic conferences, diplomatic exchanges, defensive alliances and a broad adherence of the system of the balance of power. Indeed, the patchwork of defensive alliances that grew up before 1914 was testament to the fact that no European state felt a sufficient a degree of confidence to manage its own defence alone.
