The League of Nations in the 1920s
A New Idea for International Order
One of Woodrow Wilson’s Fourteen Points called for an international organisation capable of resolving disputes peacefully before they escalated into war. The result was the League of Nations, which came into existence on 10 January 1920 when the Treaty of Versailles formally took effect. It was the first permanent intergovernmental organisation of its kind in history.
The League’s structure had four main bodies: the Assembly (all member states, meeting annually), the Council (great-power core with permanent and elected members), the Permanent Court of International Justice, and the Secretariat (the administrative office). Specialist commissions — including the International Labour Organisation and the Health Organisation — handled technical matters.
The Missing Members
The League began with a fundamental structural problem: the United States never joined. Despite Wilson’s central role in its creation, the US Senate refused to ratify the Versailles Treaty in November 1919 and again in March 1920. Republican senators, led by Henry Cabot Lodge, feared the League’s commitments would drag the USA into future wars without Congressional approval. American absence meant the League lacked the economic and military weight of the world’s rising superpower.
Germany was excluded from membership until 1926, when the Locarno spirit temporarily eased tensions. Russia was also absent — the Bolshevik government was not recognised by most Western states until the late 1920s, and the Soviet Union was only admitted in 1934. These absences meant the League spoke for a limited section of the world and could not act decisively when major powers defied it.
The League’s Successes in the 1920s
Despite its limitations, the League achieved genuine successes in the first decade. Its humanitarian work was wide-ranging. Fridtjof Nansen was appointed the League’s first High Commissioner for Refugees. He devised the Nansen passport — an internationally recognised identity document for stateless people — which helped hundreds of thousands of displaced persons after the First World War and the Russian Revolution. Nansen was awarded the Nobel Peace Prize in 1922.
The League’s International Labour Organisation worked to improve working conditions globally, setting minimum standards for hours, wages, and child labour. The Health Organisation (a predecessor of the World Health Organization) co-ordinated international responses to typhus outbreaks in Russia and Eastern Europe. The Slavery Commission monitored conditions in territories where the practice had not been formally abolished.
The League successfully resolved several territorial disputes that might otherwise have led to conflict. In 1921, Sweden and Finland both claimed the Aaland Islands. The League’s commission awarded them to Finland, with guarantees for the Swedish-speaking population, and both nations accepted the verdict. In 1925, the League settled the border dispute between Turkey and British-controlled Iraq over the oil-rich Mosul region, awarding Mosul to Iraq.
The Vilna and Corfu Crises
The League’s record against powerful states was less impressive. In 1920, Polish General Lucjan Żeligowski seized the city of Vilna from Lithuania with troops officially acting outside Polish command. The League condemned the action but took no practical steps to reverse it, and Vilna remained under Polish control. Lithuania refused to accept the outcome and the two countries remained in a state of formal hostility for the rest of the decade.
The Corfu incident of 1923 was more damaging. After five Italian officials surveying the Greek-Albanian border were murdered in Greek territory, Italian Prime Minister Benito Mussolini ordered the bombardment and occupation of the Greek island of Corfu. Greece appealed to the League, whose Council condemned the Italian action. However, Mussolini refused to accept League jurisdiction and threatened to withdraw Italy from the organisation. Under pressure, the League passed the matter to the Conference of Ambassadors, which ordered Greece to pay compensation to Italy — a humiliating reversal. Italy had defied the League and emerged better off.
The Corfu incident showed that the League could be openly defied by a major power and would back down rather than impose sanctions. Mussolini’s Italy used force, ignored the League’s ruling, and paid no penalty. This revealed a critical weakness: the League had moral authority but lacked the military force to compel obedience from powerful states.
The Geneva Protocol and Disarmament
In 1924, the League’s members drafted the Geneva Protocol, which would have committed members to submit all disputes to arbitration and to act collectively against any state labelled an aggressor. It was seen as a way to close the gaps in the League’s Covenant. However, the newly elected Conservative government in Britain refused to ratify it in 1925, citing concerns about imperial commitments, and the Protocol never came into force.
Disarmament remained an unfulfilled aspiration. The Versailles Treaty had disarmed Germany on the explicit understanding that other nations would follow. Yet France, with memories of two invasions, was unwilling to reduce its forces, and the World Disarmament Conference convened in 1932–34 ultimately failed without agreement. Germany’s resentment at being the only disarmed major power grew throughout the decade.
Historians point to several structural weaknesses that limited the League’s effectiveness beyond the 1920s crises. Decisions of the Assembly required unanimity, giving each member state an effective veto. The absence of the USA, Germany, and the USSR meant the League never represented all the major powers simultaneously. It had no standing army of its own and depended entirely on member states volunteering forces — something they were reluctant to do during economic hardship. Economic sanctions, the League’s main non-military tool, required all members to participate to be effective; partial sanctions simply shifted trade to non-participating countries. These weaknesses became fatal in the 1930s when authoritarian states openly challenged the international order.