The League of Nations was formed after World War 1 to encourage cooperation between countries and maintain peace. It had early successes resolving land disputes and aiding refugees. However, its weaknesses led to failures. Major powers like the US and USSR did not join, it had no army, and it could not effectively sanction aggressors due to its decision-making structure requiring full agreement. This was shown in 1935 when Italy invaded Abyssinia despite League sanctions.