National Archives: German troops parade through Warsaw, Poland. PK Hugo J„ger, September 1939

Although the invasion of Poland is considered the action that started World War II, there were many other actions and circumstances that led to that point. In fact the first aggressive acts were not committed by Germany but by Italy and Japan.
        The entire world was enduring an enconomic depression from 1929 through the start of the war. Food and other necessities of life were scarce and many people struggled to provide for their families. The people were suffering because of this depression and sought solutions to their problems. People in hopeless situations often grasp at anything to save themselves. In the countries of Italy, Japan and Germany power hungry men offered their people a straw. If the people would back them, they would lead their countries to rule the world and let the vanquished do the providing for the conquerers.
        The first to act was Japan. Hirohito had convinced his people that aggression and domination was their only road to security. The occupation of Manchuria began in 1931 and was largely ignored. Although the United States objected and through diplomatic means tried to intervene, there was little or no support from home. America wanted to isolate itself from foreign problems.
The next to act was Italy, who under the command of Benito Mussolini invaded Ethiopia in October of 1935. Mussolini promised his people to return to the days of the Roman Empire. The new Empire would absorb all of the Mediteranean basin as well as some northern parts of Africa. The ineffective League of Nations passed sanctions, but little else was done.
        The Treaty of Versailles, which ended WWI in 1919, forbade armament production and development in Germany. It divided the border areas and gave control to the Allied victors. Germany was limited to a small home defense army and navy.
        Ambitious leaders instead began their own private armies, not governed by the German Reichstag. Hitler's Stormtroopers, the SS were such an army.
        Hitler used many treacherous means to achieve his ends. His Fifth Columnists sowed seeds of discontent, sabotage and rioting to gain control within Germany. Hitler was a master of speechmaking and a master of deceit. In his own words, the way to succeed is to " demoralize the enemy from within by surprise, terror, sabotage, assassination. That is the war of the future." In an interview in 1933 he stated,  "I am willing to sign anything, I will do anything to facilitate the success of my policy".
        When he observed the Allies' attempts to appease him, he knew it was time to strike. He first tested the waters by invading the Sudetenland, under the mask of protecting persecuted Germans living there. In the Munich Agreement, the area was given over to him without a fight. Next he moved on to Czechoslovakia, again the neighboring powers sought to make peace.  Poland was the next step, and finally Britain declared war in defense of the Polish people and the war began...

National Archives: "The tragedy of this Sudeten woman, unable to conceal her misery as she dutifully salutes the triumphant Hitler, is the tragedy of the silent millions who have been `won over' to Hitlerism by the `everlasting use' of ruthless force."