Immanuel Kant’s Perpetual Peace (1795) might still be the most renowned philosophical voice that outlines – with mild irony – the relevance of the law (of nations) for “World Peace”. Borrowing from Kant’s insight that “war … is only the sad recourse in the state of nature (where there is no tribunal which could judge with the force of law)” (Sixth Preliminary Article), the nineteenth century saw an increasing number of successful attempts by scholars, politicians, and peace activists to put into practice third-party tribunals which arbitrated disputes between states by drawing on international law.

The modern history of interstate arbitration, we are usually told, commences with the Anglo-American Jay Treaty of 1794, which established three mixed commissions to deal with financial and border disputes left unresolved after the American Revolutionary War. As is the case for any date chosen by historians to begin their narrative, a certain arbitrariness is evident in this choice of 1794. First, historians apparently found it tempting to choose a date following 1789, thus implying that, in the aftermath of the American and French Revolutions, a new era announcing the rule of law in international relations had begun. However, the Ancien Regime also saw numerous cases of third party dispute resolution in the international arena. Second, the Jay Treaty of 1794 required the formation of several Anglo-American mixed commissions, but no third party was involved in arbitrating the disputes between both states. It thus seems that the Jay Treaty is a rather surprising, if not unconvincing starting point for one of the classic nineteenth century success stories about the imminence and inevitability of progress in law. After all, in 1812, war broke out anew between the parties.

As was the case in the centuries before the Jay Treaty and continued to be the case afterwards, war could be followed by arbitration, but war could also follow arbitration. In historical perspective, the counter-positioning of “either war or law”, as implied in Kant’s above-quoted 1795 assessment of the international order, seems incomplete. The bemoaned fact that “there is no tribunal which could judge [between nations] with the force of law” (true as it was) should not prompt one to overlook that individual state parties – without compromising their sovereign right to resort to war – were always free to decide on an ad hoc basis to refer their dispute to a disinterested third party and to agree beforehand to be bound by its decision. The classic textbooks of international law like Textor (1680), Pufendorf (1684), or Vattel (1758) repeatedly refer to historical examples of “mediation” and “arbitration”. They lay out legal implications of both – sometimes difficult to distinguish – modes of interstate dispute resolution, which were not only employed to end wars, but also to prevent states from waging war.

While the dream that states would renounce the use of force and would resolve their disputes before an international court of law continued to enthuse intellectuals in the nineteenth century, just as it had in the seventeenth or eighteenth century, state practice changed little as shown by the Jay Treaty (its non-involvement of a third-party proved to be rather exceptional) and subsequent arbitration cases. State parties continued to appoint ad hoc tribunals (often a head of state considered ‘neutral’ in the dispute, who in turn would delegate the task of resolving the issue to a[n unnamed] legal advisor).

A new element, however, was the marked increase in the number of arbitration cases after 1820. For the entire century, historians have identified more than 200 interstate cases, the majority in its second half. The most prominent examples were the Anglo-US Alabama Arbitration (1872) and the Anglo-Portuguese Delagoa Bay Arbitration (1875). The reason for the increase might be the general increase in international affairs, which augmented the chances of dispute. What types of conflicts did state leaders prefer to submit to third party arbitration? It seems difficult to recognize a general pattern given the scope of the conflicts arbitrated. The disputes concerned mostly territorial questions, debt recovery, mutual claims, maritime seizure and fisheries, arrests of nationals, private claims, or claims after (civil) war. Given that questions of national honor were often at stake when immense financial claims or boundary rectifications demands were laid before an arbitral tribunal, it would be incorrect to assume that only matters of little political relevance were submitted for arbitration.

Another new element in the politics of nineteenth century interstate arbitration was the growing support by – to use an anachronism – civil society organizations, most of all pacifists, but also academics. The nineteenth century witnessed a political paradox: While governments gained domestically in power, and nationalism seemed to be the dominant political ideology, a new vein of internationalist thought emerged: international law. Its practitioners, i.e. lawyers, were realistically oriented rather than revolutionary men. They worked towards the goal of codification and professionalization of international legal practice and had internalized the liberal belief in the civilizing power of the law. Politicians, especially in countries were pacifism gained political influence like France, Great Britain, the US, or the Netherlands, increasingly acknowledged the relevance of international law. Interstate arbitration cases were considered by many in the peace movement as resounding successes, supposedly proving the superiority of law (associated with scientific progress) over politics/diplomacy (associated with war and the ‘state of nature’). Governments were pushed to not only submit already existing disputes to ad hoc tribunals, but to also conclude formal treaties with other nations, according to which future disputes would have to be settled by arbitration. It seemed as if world peace would finally be possible and realistic, if governments no longer hid behind their state’s sovereignty that would not recognize any ‘judge’ above it, and all international disputes were submitted for arbitration by a ‘neutral’ third party arbitrator.

The manner in which these disputes were addressed was more and more similar to domestic court cases. Memoranda issued by the parties brought forward arguments of law and fact. And also, the arbitrators chosen by the parties, who were often professors of law or diplomats well versed in international law, provided the parties with awards that not only stated in whose favor the arbitrator(s) decided; instead legal reasoning was given to justify this or that conclusion, norms and precedents were quoted.

The development described here points to a correlation between tendencies of juridification on the domestic and international level. All the actors involved in interstate arbitration cases in the decades prior to the First World War oriented themselves towards national legal standards. One reason for this correlation (some have called “analogy”) between tendencies of juridification and professionalization is to be found in those lawyers who worked both on domestic and international (court) cases. These actors argued and operated on the basis of general principles of law, which led them to conclude that the differences between domestic and international law were small.

The crowning success, not only for the endeavors of the peace movement, but also for the idea of an analogy between the national and international legal system would have been, in the Kantian tradition, the world “court of law”. However, this ‘grand solution’, to have one arbitration body to which all governments could turn, was only reluctantly accepted by politicians who objected to setting up limits on state sovereignty. Only in 1899, did the First Hague Peace Conference agreed on the “Permanent Court of Arbitration”. But it was, as is often remarked, neither permanent nor a court, but merely a list of names of lawyers from which state parties could choose if they agreed to settle their dispute by arbitration. However, this procedure was not obligatory. The PCA was only hesitatingly called upon. Also in later decades, many state parties preferred to have their dispute arbitrated by ad hoc tribunals that proved more flexible than the PCA. It turned out that this story of legal progress, juridification, and betterment was in fact one of a mere transformation of old forms. Political actors were not looking for the ‘grand solution’; they saw it as minimally relevant if not expressly undesirable.

Jakob Zollmann’s article “Interstate Mediation and Arbitration: Concepts, Cases, and Actors of Third Party Dispute Resolution (17th to 19th Century)“ is part of the edited volume On Mediation: Historical, Legal, Anthropological and International Perspectives, edited by Karl Härter, Carolin F. Hillemanns and Günther Schlee.