American President Woodrow Wilson intended the League of Nations to be the primary body of a new style of international relations based on the cooperation of all of the nations of the world. The League was to be centered in Geneva, Switzerland, a neutral location. Small nations as well as large nations were asked to join, dependent on their acceptance of the Covenant of the League. The League of Nations first met in November 1920. Forty-two nations were represented at this first meeting. Notably absent were German, Russia, and the United States. Germany, identified as the aggressor in World War I, was barred from admission at first, and admitted in 1926. Russia, now the Soviet Union, was not invited to join the League due to the radical policies of the new communist government. The Soviet Union finally became a member of the League in 1935. In November 1919, the US Senate voted against accepting membership to the League, and the nation never joined.
The League of Nations operated through three agencies: the Assembly, the Council, and the Secretariat. The Assembly met annually, and consisted of a delegation from each member nation. Each member had one vote. The Council was composed of four permanent members and four nonpermanent members, serving as a sort of cabinet, with some executive powers. The Council was responsible for the prevention of war through disarmament, resolving disputes, and supervising the mandates of the League. The Secretariat was the League's civil service, preparing the agenda for the Assembly and the Council, serving a clerical purpose, and preparing documents for publication.
The League of Nations succeeded in providing assistance to bankrupt nations, supervising its mandates, and resolving conflicts between minor powers. During the early 1920s, the League made two attempts to outline a mechanism by which international conflicts could be contained and resolved. Both methods aimed to identify the aggressor nation and pledge League support to the victim. The Treaty of Mutual Assistance, the first of these two efforts, was drafted in 1923. It proposed that the Council should declare which side of a conflict was the aggressor within four days of the outbreak of the conflict, at which point the League's members would automatically have to support the victim nation. The treaty failed, due to consensus that deciding which side of a conflict was the aggressor was far too difficult to do in just four days and without any concrete guidelines. The treaty also mandated military participation on the part of the member nations, a clause distasteful to many. In 1925, the League tried once again to outline a mechanism for the containment of war. The Geneva Protocol provided for compulsory arbitration of international disputes by the League. Any nation unwilling to submit to the League's arbitration would be declared the aggressor. This proposal was brought down by the British delegation, whose overseas colonial leaders feared that they would be dragged into European affairs by the Geneva Protocol.
The League of Nations was at first heralded as the bastion of a new system of international relations in Europe. The so-called 'old diplomacy' is known as the Westphalian System, since it had been in place since the Treaty of Westphalia, signed at the end of the Thirty Years War in 1648 by the major European powers. Under the Westphalian system the elites of government often met in secret to determine the fate of Europe and the world. World War I shattered the old system along with the empires that had maintained it. American participation in the war was a major step toward a shift in the balance of world power, and the beginning of the end for European dominance. The brutality, and to some, apparent needlessness, of the war and the changing face of European geography led to new ideas about how international affairs should be managed. The secretive nature of the Westphalian system had led to petty resentments, the pursuit of narrow self-interest, and the division of Europe into warring camps. Many, including Woodrow Wilson, felt that a more open, all- inclusive system would be more fostering to cooperation, a concept of international justice, and peace. The League was seen as a way to institutionalize these goals and strive for peace as a collective world community.
The League of Nations was an organization wracked by contradictions and insufficiencies from the start. Membership was determined by the acceptance of the Covenant of the League, which stated the goals and philosophy upon which it was founded. The covenant, however, had been drafted by small committees behind closed doors, thus violating the spirit of "open covenants openly arrived at" expounded by the Covenant of the League itself. This contradiction foreshadowed similar crises of ideology in the future for the League. The United State's failure to join the League of Nations was a major blow to the hopes of its founders, and to Wilson's view on the character of the 'new diplomacy.' It also marked the beginning of a period of US isolationism, which kept the US effectively out of European political affairs for the majority of the inter-war period.
The founding and structure of the League of Nations was established primarily for the purpose of preventing future wars, a new concept for Europeans who traditionally believed that war was a necessary and inevitable outgrowth of international relations. However, the League could not come to a decision on how best to do this, without infringing on the sovereignty of the member countries, as would have been the case if the Treaty of Mutual Assistance or the Geneva Protocol had been passed. The failure of these two measures left the League with only the power to invoke economic sanctions against a nation determined to be the aggressor in a conflict, and greatly called into question the authority and ability of the League to mediate conflicts. The League of Nations thus exercised only limited powers, and did so clumsily. Most powerful nations preferred to manage their affairs outside of the League, only rarely deferring to the League's authority. Despite these shortcomings, the League of Nations did accomplish some of its unification and pacification goals, and perhaps most importantly, set the stage for the United Nations, which would take its place after World War II.