The diplomatic philosophy behind the League represented a fundamental shift from the preceding hundred years. The League lacked its own armed force and depended on the Great Powers to enforce its resolutions, keep to its economic sanctions, or provide an army when needed. However, the Great Powers were often reluctant to do so. Sanctions could hurt League members, so they were reluctant to comply with them.
When, during the Second Italo-Abyssinian War, the League accused Italian soldiers of targeting Red Cross medical tents, Benito Mussolini\ responded that "the League is very well when sparrows shout, but no good at all when eagles fall out."
After a number of notable successes and some early failures in the 1920s, the League ultimately proved incapable of preventing aggression by the Axis power in the 1930s. Germany withdrew from the League, as did Japan, Italy, Spain and others.
The onset of World War II showed that the League had failed its primary purpose, which was to prevent any future world war. The League lasted for 27 years.