After the Treaty of Versailles there were still unresolved disputes after the war where countries disagreed with the terms .There was continued violence and uncertainty. The League had to resolve international crises some were sorted out successfully some though were not.
The economic collapse of Austro-Hungary caused by payment of reparations led them to the verge of bankruptcy. The League took over management and Austro-Hungary began economic recovery. In this case the League was prompt and effective in solving the crisis.
After the treaty of the Neuilly Border there was friction between Greece and Bulgaria. The Greeks invaded Bulgaria in 1925, and then were condemned by League so they withdrew. The League was successful and brought peace but there were no major powers involved.
In 1921 the Aaland Islands located in the Baltic Sea between Sweden and Finland, both nations claimed them and were willing to fight. The League intervened and awarded them to Finland. This was successful because both nations were willing to accept the Leagues authority they were not major powers.
In Upper Silesia a German/Polish plebiscite area, defined by the treaty. Both Poland and Germany wanted to occupy it, Plebs voted to become German. This was a messy compromise which caused bitterness between the two countries.
In 1920 Vilna was Lithuanian but the population was Polish and it was occupied by Polish forces. The League tried to negotiate but this confirmed the occupation in 1925 fighting continued until 1927.The League were weak and useless when dealing with a large country like Poland, they did not bring peace and their intervention did not help.
In 1923 five Italian surveyors were shot on the Albanian frontier by Greece. In revenge Mussolini invaded and occupied Corfu, in complete defiance of the League. The League were too weak to condemn Italy, so they told Greece to accept Italian demands .Greece paid compensation for the shootings and apologised, then Italy left Corfu. This was a disaster for the League when confronted by major powers willing to use force the League backed down.
The disputes that were sorted out successfully were the ones in which major powers did not confront the League, and were willing to accept the League’s authority. The League was not as powerful as it seemed because it had no armed forces of its own, it relied totally on the cooperation of France and Britain, if they did not want to take action the League was powerless. The League would only ever invade a country as a last resort because it was so expensive France and Britain were unwilling to use their troops because still recovering from WW1.When League member Japan invaded Manchuria no action was taken against the aggressor. The League was weak when League members misbehaved. This was a serious flaw in the League’s plan for world peace because it could be seen as a ‘victor’s club’ where major powers had all the power to do what they wanted.
Other tasks the League took on were agencies and commissions such as the International Labour Organisation which was an important body for workers and they strongly campaigned for better working conditions. The World Health Organisation was part of the League and started a campaign to exterminate mosquitoes to help stop malaria
France was a major power in the League but she did not have full faith in its ability to protect her from Germany. So the French Government broke the rules by organising a network of alliances outside the League with countries who would help her if Germany attacked again. All League members had different self interests so if France was invaded it would not be certain whether fellow League members would be willing to help use force to assist. Major powers did not share Frances fear of attack from Germany.
The main flaw of the League was the conflict between the self interest of main member countries and the interest of the League; if the two conflicted there would be little chance of any effective action.
The League was a partial success in the 1920’s with the success of agencies working effectively; resolving the Greek/Bulgarian incident, The Aaland Islands and helping Austria-Hungary overcome a financial catastrophe. But there were more serious disputes involving France, Italy and non-member Russia which were more difficult to resolve. The League contained 42 nations and this was a downfall because not all nations were involved such as Germany (because they lost the war) Russia (communist) and USA (because they wanted to stay out of European affairs).So these countries did not come under the rules of the League so were free to do what they wanted. Some countries regarded the League as being unimportant and in its final years the League proved too weak and lacking in power to stop the rise of Hitler and the Japanese invasion of Manchuria. Although the League collapsed it was the first association to tackle with world issues and lessons were learnt from the mistakes made to help organisation like the United Nations and NATO.