During the 1930s, several dictators, such as Adolf Hitler, Benito Mussolini, and Emperor Hirohito, pursued aggressive foreign policies that threatened global peace and stability. In response, the League of Nations and world leaders took a number of steps to try to contain and deter military aggression.
The League of Nations was established after World War I with the goal of preventing future wars. However, it was largely ineffective in the face of the aggressive actions of dictators in the 1930s. One of the League's first major tests came in 1931 when Japan invaded Manchuria, a region in northern China. The League condemned Japan's actions, but Japan withdrew from the League and continued its military expansion.
In 1935, Italy under Mussolini invaded Ethiopia, violating international law and the League of Nations' rules. The League imposed economic sanctions on Italy, but this failed to stop Mussolini's aggression.
The response of world leaders to military aggression during the 1930s was mixed. Some, like British Prime Minister Neville Chamberlain, pursued a policy of appeasement towards aggressive dictators, hoping to avoid war by making concessions. Others, like French Prime Minister Édouard Daladier and U.S. President Franklin D. Roosevelt, took a tougher stance against aggression.
In 1938, Hitler's annexation of Austria and threats against Czechoslovakia led to the Munich Agreement, in which Chamberlain and other leaders agreed to give Hitler control of the Sudetenland in Czechoslovakia in exchange for a promise of peace. However, Hitler later broke this promise and invaded Czechoslovakia in 1939.
Ultimately, the League of Nations failed to prevent World War II, as aggressive dictators continued to pursue their expansionist policies despite international condemnation. The war ended with the defeat of Germany, Italy, and Japan, and the establishment of the United Nations as a new international organization dedicated to preventing future wars.