It is a truth universally acknowledged – or at least it should be1 – that the importance of arbitration between States extends beyond the subject matter of the arbitrations themselves and has wider implications for the peace of the world. The idea that wars can be avoided if States have access to peaceful means of settling the disputes which might lead to war has played an important part in international relations for at least 150 years. Yet it is an idea which has waxed and waned in popularity. Its apogee was in the last decades of the nineteenth century and the first years of the twentieth. At that time there were many – by no means all of them international lawyers – who saw international arbitration as one of the principal instruments for preserving the peace.2 That idealism waned after the World War I.