Adolf Hitler is dictator of Germany. He came to power by convincing the German people that they were a super race, a perfect race, and they believed it. The Nazi party invaded: Poland, Denmark, Norway, Luxingburg, France, The Netherlands, And Belgium.
Benito Mussolini is the dictator of Spain. He came to power by forming right wing groups, and quickly coming into power over Italy by force. The Facists Party invaded: Ethiopia
Francisco Franco is dictator of Spain. He came to power by disciplined himself, and quickly moved up rank, but came to full power with the help of Benito.
Joseph Statlin is the dictator of the Soviet Union. He came to power by moving up, and building a base, when soon he overthrew the high placemented and soon every one owed there attention to him.
Hideki Tojo was dictator of Japan. He came to power by overthrowing the government. His Party invaded the northerner part of Asia, and the pacific.
The way the US got into this is because of The Pearl Harbor attack. They were trying to stay neutral, but the Japanese attack pulled them in to the war.