Notes

By the 1930s, extreme nationalists had gained power in Italy, Germany, and Japan, which became known as the Axis powers. By seeking to expand through military conquest, these countries began World War II. In 1941, the United States entered the war as one of the Allied powers.
Totalitarianism In 1924, Joseph Stalin became the dictator of the communist Soviet Union. Nazi dictator Adolf Hitler gained power by promising to restore German strength. He built up the German military and began a campaign of expansion. Similar actions took place in Italy under dictator Benito Mussolini and in Japan under Japanese militarists.
Munich Pact Great Britain and France tried to appease Hitler. In the Munich Pact, they agreed to give him part of Czechoslovakia in return for peace. But Hitler continued with territorial expansion. Germany’s invasion of Poland in 1939 triggered World War II.
Neutrality Acts A series of neutrality acts in the 1930s kept the United States from being drawn into European conflicts, including the Spanish Civil War. As World War II began, however, Franklin Roosevelt and Congress revised the acts to allow arms trading with the Allies.
Lend-Lease Act Germany quickly occupied most of Europe and threatened to invade Great Britain. As German bombers ravaged British cities, the United States decided to help Britain by passing the Lend-Lease Act. This law allowed the United States to lend arms to Britain and, later, to the Soviet Union.
Attack on Pearl Harbor On December 7, 1941, Japan attacked the U.S. Pacific Fleet at Pearl Harbor. This attack caused the United States to declare war on Japan and enter World War II.