What was the most important cause of the Second World War?

[Note at least three potential causes of WWII] Three causes of WWII include: the Treaty of Versailles; the Great Depression; and the policy of Appeasement. [Contrast cause 1 with cause 2, and then cause 3 (your most important cause) with 1 and 2] The Treaty of Versailles placed an incredible economic strain (>100bn marks of reparations) on the German economy, leading to hyperinflation which destroyed Germans’ savings building resentment. This resentment was added to by the War Guilt clause, extreme limits on the German military, and loss of territory, such as Alsace-Lorraine and (temporarily) the Saar, which was also a economic blow given its coal mines. However, these factors would not have been as intense had it not been for the Great Depression, which ended international investment in Germany, led to the recall of loans, and so helped to crash the German economy. It was in this extreme economic scenario that the Nazis and Communists gained support (the latter helping in the rise of support for the former), which in turn allowed for Hitler to acquire sufficient control of the Reichstag to takeover the government as he had been unable to do via the Munich Putsch despite the Treaty of Versailles having been in force for four years.The policy of Appeasement, however, allowed Germany to be in a position where its resentment and subsequent Nazi political gains could translate to the outbreak of war. If the Treaty of Versailles’s military restrictions had been enforced by the initially more powerful victors of WWI (Britain and France), then the German military would have been unable to feasibly being WWII. Moreover, if initial German expansion (militarising the Rhineland, the Sudetenland, and then the rest of Czechoslovakia) had been checked Germany would have been less willing to attack Poland and France, having failed in these previous smaller attempts.