The forerunner of United Nations was the League of Nations, an organization conceived in similar circumstances during the First World War, and established in 1919 under the Treaty of Versailles 'to promote international cooperation and to achieve peace and security'. The International Labour Organisation was also created under the Treaty of Versailles as an affiliated agency of the league. The League of Nations ceased it activities after failing to prevent the Second World War.
The League of Nations was the first experiment to establish and international organization in the political field. One of its main short comings was that it was primarily aimed to preserve existence consequent on the Treaty of Versailles of 1919. The other major reasons for its failure were :
1. It lost its universality of membership.
2. Basically it acted as European club.
3. President Woodrow Wilson, one of the founding fathers of the League of Nations was not allowed to join the League of Nations, because the US senate refused to ratify the government of the League.
4. The League of Nations failed to prevent the aggression and conquest of Manchuria (north - east of china) by Japan in 1931.
5. It also failed to prevent the aggression of Abyssinia (Ethiopis) by Italy under Mussolini in 1935.
6. the emergence of dictatorship and the eclipse of democracies in many parts of Europe was another important factor.
7. The emergence of Nazism in Germany and the rise of Adolf Hitler.
8. The League had no role to play in the field of international economics.
9. The US congress reduced its contribution to the League budged by 25%.
10. It failed to enforce its resolutions against aggressive nations. (Japan, Germany and Italy).