The peace settlement entered into at Versailles created more problems than it solved, and thus was a direct and integral cause of World War II. A number of factors were involved, most related to Woodrow Wilson's insistence on the creation of a League of Nations. Wilson was so intent on creating the League that he agreed to a number of terms which in the long run proved quite unfortunate. Among them:
Article 231 of the Treaty, the famous "war guilt clause," by which Germany was forced to accept complete and total responsibility for the war. This was an oversimplification at best:
The Allied and Associated Governments affirm and Germany accepts the responsibility of Germany and her allies for causing all the loss and damage to which the Allied and Associated Governments and their nationals have been subjected as a consequence of the war imposed upon them by the aggression of Germany and her allies.
As a followup to Article 231, Germany was required to assume responsibility for the total cost of the war:
The Allied and Associated Governments, however, require, and Germany undertakes, that she will make compensation for all damage done to the civilian population of the Allied and Associated Powers and to their property during the period of the belligerency of each as an Allied or Associated Power against Germany by such aggression by land, by sea and from the air, and in general all damage as defined in Annex l hereto.
These provisions, unfair per se, caused deep resentment among the German people and provided a ready platform for Adolf Hitler. Hitler constantly railed about the unfairness of the Treaty which gained him tremendous support.
Additionally, the Treaty, pursuant to Wilson's Fourteen points, called for the creation of an independent Poland with access to the sea. Creation of Poland was not per se a problem, however the terms of the Treaty carved out an area of German speaking people and awarded it to Poland. It also severed a portion of Germany from the mainland. The disregard of the national interests of the people within the Polish corridor again gave Hitler a convenient platform.
Finally, Japan had entered the war on the side of the Allies, expecting to receive former German territories in Asia. Instead, it left the conference empty handed. This provided fuel for Japanese nationalists and imperialists to push Japan to take territories in Asia without sanction from its former Allies. Japanese soldiers, in attacking Manchuria and other areas, used as their battle cry, "Asia for Asians."
It was thus the bungled nature of the Versailles Peace settlement which sowed the seeds which later erupted into World War II.