1. The Japanese Invasion of Manchuria (1931)
The League of Nations survived the 1920s because there were no serious crises to challenge its effectiveness.
When Japan invaded the Chinese province of Manchuria in 1931, China appealed to the League for help.
Japan ignored the League’s requests to withdraw from Manchuria, and withdrew from the League of Nations instead. The League faced a disturbing reality: they had no real control over countries that would not recognize the League’s authority.
Because most nations were in the grip of the Great Depression, few countries wanted to refuse trade with Japan.
Neither Britain or the U.S. was prepared to use its naval forces to blockade Japan.

2. The Italian Invasion of Abyssinia (1935)
In 1935 there was a border clash between Italian Somaliland (Somalia) and Ethiopia (Abyssinia).
The Italian dictator – Benito Mussolini – used the League of Nations’ inability to solve the Manchurian Crisis as an opportunity to take over Abyssinia.
Mussolini’s full-scale attack involved Italian tanks and aircraft attacking Abyssinians with spears.
The League of Nations immediately imposed a boycott against trading with Italy, but again, many countries did not comply.

3. German Expansion
1933: Hitler becomes Chancellor of Germany with the slogan, “Today, Germany. Tomorrow the World!” He immediately expands the German Army & Air Force – breaking the terms of the Treaty of Versailles
1936: German troops march into the Rhineland – something that is forbidden under the Treaty of Versailles. No one stops the German advance
1938: In March, Germany annexes Austria. Not a single shot is fired.
1938: In September, Hitler takes over the Sudetenland – part of Czechoslovakia inhabited by ethnic Germans.
1938: The Munich Pact is signed. England & France allow Germany to keep the Sudetenland in order to avoid war.
1939: In March, Hitler takes over the rest of Czechoslovakia
In early 1938, Austrian Nazis conspired for the second time in four years to seize the Austrian government by force and unite their nation with Nazi Germany. Austrian Chancellor Kurt von Schuschnigg, learning of the conspiracy, met with Nazi leader Adolf Hitler in the hopes of reasserting his country's independence but was instead bullied into naming several top Austrian Nazis to his cabinet. On March 9, Schuschnigg called a national vote to resolve the question of Anschluss, or "annexation," once and for all. Before the plebiscite could take place, however, Schuschnigg gave in to pressure from Hitler and resigned on March 11. In his resignation address, under coercion from the Nazis, he pleaded with Austrian forces not to resist a German "advance" into the country.
The next day, March 12, Hitler accompanied German troops into Austria, where enthusiastic crowds met them. Hitler appointed a new Nazi government, and on March 13 the Anschluss was proclaimed. Austria existed as a federal state of Germany until the end of World War II, when the Allied powers declared the Anschluss void and reestablished an independent Austria. Schuschnigg, who had been imprisoned soon after resigning, was released in 1945.

4. The Non-Agression Pact (1939)
In August 1939, Hitler (Germany) signs a pact with Stalin (Russia).
THE DEAL:
The two countries agree not to fight each other if there is a war
They will also secretly divide Poland between them
Hitler no longer has to fear fighting the Russians if war breaks out.
1 September 1939: Hitler invades Poland
3 September 1939: Britain & France declare war on Germany. World War II begins