World War I had left behind trail of devastation in Europe, with more than 8.5 million lives lost and the European economy in ruin. At the Paris Peace Conference that ended the War, the leaders of the world felt an urgent need to provide a forum for resolving international disputes, and to promote spirit of internationalism. As a result, the League of Nations (LoN) was formed in 1920 to stop wars as well as to promote disarmament.

Achievements of League of Nations

• City of Vilna, which in 1920 was occupied by Russia, was returned to Poland after LoN's involvement.
  
  
• It also resolved a dispute between Germany and Poland over upper Silesia in 1921.
  
  
• LoN also successfully resolved issues involving smaller nations on many occasions, including between Finland and Sweden over Aaland Island in 1920, a border argument between Albania and Greece, disputes between Hungary and Rumania etc.
  
  

Failures of League of Nation

• When it came to issue involving bigger powers, the League failed miserably.
  
  
• The Manchuria crisis in 1932 was a major failure of LoN. Japan invaded Manchuria in China but the League could do nothing to help China against Japanese aggression.
  
  
• When Russia, which was not a member of the League, attacked a port in Persia in 1920, the League refused to take part.
  
  
• The League's efforts at disarmament also failed to halt the military build-up by Germany, Italy, Spain and Japan during the 1930s.
  
  

Reasons for the failure of The League of Nations:

1. Complicated mandate: The League was burdened with impossible responsibility of maintaining the treaty of Versailles which had serious practical and moral defects.
   
   
2. Narrow international support: The League was largely an Anglo-French affair, as the US did not join while Germany was not allowed to join till 1926 while Soviet Union joined only in 1934.
   
   
3. Lack of military: The League did not have any military forces of its own and was dependent on voluntary contributions of member of nations, which limited its ability to enforce decisions.
   
   
4. Countries unwilling to give up autonomy:Some European countries also did not want to give up their autonomy when seeking help with disputes.
   
   
5. Fear of failure: The league was afraid that bigger non-member powers like Russia would not acknowledge their jurisdiction if it intervened too much and that would damage the League’s authority.
   
   

The onset of the Second World War demonstrated that the League had failed in its primary purpose, the prevention of another world war. Although the League was unable to fulfill the hopes of its founders, its creation was an event of decisive importance in the history of international relations. The League was formally disbanded in April 1946 with its powers and functions transferred to the nascent United Nations.