Attitude of the U.S. Before Pearl Harbor. Public opinion in the United States was divided. Although most Americans favored the Allied cause, there was strong opposition to even indirect involvement in the war. The German-American Bund and the America First movement were especially active in opposing aid to the Allies. The American Communists also opposed aid—until Germany attacked the Soviet Union; then they demanded immediate intervention.
This World War II timeline highlights important dates from September 1939 to April 1940. This time period saw the official start to World War II on September 1, 1939 when Germany invaded Poland. Follow the events of World War II and the German invasion.
War Begins. In the early hours of Friday, September 1, 1939, the German armies stormed across the Polish frontierwithout a declaration of war.