This study analyzes the first century of the evolution of international adjudication as a permanent fixture of the international society. Through a case study approach, examining specific international courts, the study seeks to demonstrate the various limitations to effective adjudication on the international plane. By examining the ‘Hague System’ of adjudication, as manifest in the Permanent Court of Arbitration and the World Court, the structural limitation of a system predicated on volunteer acceptance of adjudication is drawn out. Beyond this most important limitation to ensuring full respect of the international rule of law, the 1908 Central American Court of Justice is considered to demonstrate the political machinations which can impede and, in this case, ultimately destroy an international court. Focus then shifts to a comparative study on the Inter-American and European courts of human rights during the 1980-1998 era to demonstrate how limits in financing and staffing reduced the Inter-American Court to a shadow of its European counterpart despite appearing similar on paper. The role which judges play in the process of adjudication is the final limitation which is considered. Various cases before the Yugoslav Tribunal are taken into account to demonstrate the extent to which judges have sought to establish an “effective’ international criminal law system often at the expense of the rights of the accused. Finally, the European Court of Justice is examined to demonstrate that the rule of law can be effectively implemented internationally if States so desire and that it is simply the intransigence of States, over the last century, which has limited the rule of law on the international plane.