The Failure of the league of nations
The Membership of the League had a poor start. First, the idea of the League came from Woodrow Wilson. But the USA refused to join. This left Britain and France, but they weren't strong enough to carry out the duties of the League after WW1. It was often the cases of self interest that these two nations resorted too. In Manchuria, Britain and France were unwilling to send their armies nor fleets, in Abyssinia, they did not close the Suez Canal , which could have stopped Mussolini's invasion and they did not ban important war materials such as coal, oil and steel. The USSR was the only country powerful enough to send troops to force the aggressors into accepting the League's wishes, but they weren't in the League. Without the USA, the League was permanently weakened. Had the USA been in the league, Japan wouldn't have conquered Manchuria and Mussolini would have backed off Abyssinia.