Causes of World War 2
Foreign Problems
Invasion of Poland
Pre War Climate
Economics
Failures of the Treaty of Versailles
Great Depression
Created foreign resentments that aligned many with the policies of particular political movements.
Disappointments
Italian promises were not fulfilled
Created a State of Unrest
Injustices
Failures of the League
Failure of Appeasement
To the larger countries, it was not worth it
Started with negotiations about the Sudetenland, led to Hitler receiving all of Czechoslovakia
Inspired Hitler to go further
Deterred potential allies
Demolished efforts for collective security
Weakened the reliability of the League even further
Particularly inspired Stalin to align the USSR with Nazi Germany. Despite the ideological differences and open hatred of Germany, Stalin and his advisors likely felt that this would give the USSR time to rearm, rather than depending on the Capitalistic British and France who would probably throw him under the bus anyway.
Supported by Great Britain's allies and the British populous
(Parliament is Democratically elected)
British led the efforts
September 1, 1939, Hitler invaded Poland from the west while the Soviet Union invaded from the east
Essentially the straw that broke the camel's back, finally convincing Chamberlain that the Nazis couldn't be diplomatically reasoned with and that force was necessary
Disunity
Members were never truly a united front. The concept of Collective security was quickly broken down by smaller versions of the League that weren't as collective
British appeasement offered Germany the green-light to rearm in exchange for a promise for peace. Hitler did not accept, but recognized the British’s reluctance to take any action against German rearmament.
Faulty Structure
Activity Structure and the inclusion of contrasting "permanent members" made it exceedingly difficult to actually get anything done
The League was unable to handle non-members, meaning that when Germany left the league after the 1933 Referendum, there was little control that the League exerted on the country.
Foreign Aggression
Fascist Italy
Imperial Japan (I guess?)
Nazi Germany
Czech Crisis
Meeting between Benes and Heinlein sees Benes surprisingly concede to yet more Nazi demands, which included Home Rule for Sudeten Germans. This inspired Hitler to push further.
After rumors about Operation Green spread to Czechoslovakia, the Czech army mobilized. Hitler saw this as an "act of aggression" and replied with mobilization, drawing the attention of French PM Daladier and British PM Chamberlain.
Berchtesgaden, Bad Godesberg, Munich Conference
After the Munich conference, the Czechs were told that if they wanted to keep the territory, they would have to fight Germany alone. But if the Czechs gave in now, the others would protect their future independence. Thus, on October 1st, 1938, Czech frontier guards abandoned post and the German troops now occupied the Sudetenland. Polish and Hungarian troops even also came to seize territory.
While Hitler publicly signed an agreement that promised to end territorial claims in Europe, he was secretly planning "operation white" to occupy the rest of Czechoslovakia in March 1939.
May Crisis: Benes Mobilizes, Britain and France Issue Warnings, Nazis back down, Hitler orders "Operation Green" to take the Sudetenland
Hitler demanded the return of Memel (in Lithuania) and Danzig (in the Polish Corridor). The UK definitely promises to protect Poland in the Anglo-Polish Treaty and begins serious Rearmament
Hitler sort of always wanted war to begin. He was ready for a long time
Alliances
Molotov-Ribbentrop Pact
Nazi-Soviet Non-Aggression Pact
Distrust
Failures of the League of nations (literally)
Anschluss
Spanish Civil War
Abyssinia
Munich Conference
German Rearmament of the Rhineland
Czechoslovakia
Manchuria
Stalin expected France to break Franco-Russian pact they had made in 1935
Unreliability
Many British Tory and citizens welcomed a Strong Germany as a force to fight Communism. Many Tory MPs were extremely critical of the USSR in the press, and Chamberlain thought that aligning with the USSR would deter smaller countries against the allied powers.
Chamberlain saw the guarantee as a warning to Hitler but Stalin saw it as a support for a potential enemy
Germany felt that they had been improperly punished by the Treaty. The repercussions and following actions from other countries promoted the November myth and traitors within the Jewish and Slavic communities.
Failure to solve the widespread problems led to discontent with established governments, making it more plausible for those most heavily effected by the Depression to sway to political extremes and away from the establishment.
Sanctions
Italy after the Invasion of Abyssinia: Completely useless against Italy itself, and demonstrated the weaknesses of the League. It's reliability and strength further deteriorated.
Japan after the invasion of Manchuria: provoked Japan and essentially begins the process of their abandonment of the League.
Tripartite Pact
Pact of Steel
Practically directly led to the crisis of Manchuria and Abyssinia, both of which were catastrophic for foreign relations and opened the door for imperialistic desires to flourish.