1. Treaty of Versailles
When the treaty was called, Woodrow Wilson had a desire "peace without victory". He did not want to punish Germany for the First World War, in fear that doing so could lead to another war. France and Britain had something else in mind. The cost WWI was put on Germany, and the reparations would put Germany into a great economic hardship. The hardship led to the people of Germany to feel vulnerable and in need of a new government. This is why the Nazi Party was able to take control in the 1930's so quickly and swiftly.
2. America's Isolationism
America's isolationism all started with Woodrow Wilson and not joining the League of Nations back at the end of World War I. With the League of Nations without America and Woodrow Wilson’s guidance and beliefs, it is unable to prevent the European countries from starting conflicts again, which was its main purpose. All the while America is becoming a neutral power in the world, totalitarianism is rising in countries like Italy, USSR, Germany, Spain, and Italy. Italy is experiencing a revolution. Italy invades Ethiopia. Germany takes over the Rhineland. Europe is lost with the isolationism of the democracy that America withholds inside their government.
3. Nazi Germany Remilitarizes
On March 23, 1933 the Nazi Party, led by Adolf Hitler, came into power in Germany by passing the Enabling Acts. Two years later, with internal affairs under steady control, Hitler ordered the remilitarization of Germany by increasing soldiers in Luftwaffe (air force), and in the infantry. This violated the Treaty of Versailles, signed after WWI. Further violating the treaty, Hitler ordered the Rhineland to be militarized, which is the land in between France and Germany. This of course worried France, causing them to remilitarize in self defense. Thus, the ripple effect of remilitarization in Europe occurred. The region was bound for another war.
4. Nazi-Soviet Non-Aggression Act
This “non-aggression” diplomatic way of handling an alliance with Russia allowed Germany to stall on the backstabbing of Russia. Germany made an alliance with Russia to not declare war on each other, which relieved the western front for Hitler and his troops. The Germany military could now completely focus their fight on the eastern front and advancing on the countries to the east. This led to the quick invasion of Poland, France, and others, with all of the firepower in one place. If Russia was occupying the western front, then perhaps the invasions to the east would not have been so severe and the war might have not begun. Unfortunately for Russia, the Nazi’s gained the east and had nothing left to do but invade the west. The Russians would be turned on by the Germans.
5. Sudetenland and Czechoslovakia
In 1938, with the new alliance with Austria, Germany was beginning to feel its ability to execute its plan. The Nazi power moved into Czechoslovakia under peaceful terms, at first. The new radical government took control of Sudetenland, which was a German speaking area of Czechoslovakia. This caused many countries of Europe to become tense, countries like France. This also led to the remilitarization of some European countries, not wanting an invasion of this sort to occur to them. In September 1938, the Munich Conference was called, where Germany made the argument that they were done capturing land. Eventually, Hitler would take the rest of Czechoslovakia, lying about the discussions at the Munich Conference. This set the tone of the Germany’s and that they would not let diplomatic means get in the way of Hitler’s master plan.