Each went to war against Germany at different times and for different reasons. Britain, the Soviet Union, and the United States were not allies before they went to war, as Britain and France were. The lineup of countries fighting the war was complicated, as were their relationships with one another. The United States and Britain were at war with Japan. The United States, Britain, and the Soviet Union were now fighting Germany. A few days later, Germany and Italy declared war on the United States. In December 1941, Japan bombed Pearl Harbor in Hawaii and attacked British and American possessions in the Pacific. In June 1941, Germany invaded the Soviet Union, which then allied with Britain. Originally, the major Allies were Great Britain and France, but France surrendered to Germany in June 1940. The countries fighting them were called the Allies. Several other countries were members of the Axis or cooperated with it at different times. The alliance of Nazi Germany, Italy, and Japan was known as the Axis. Two sets of countries fought World War II.

Axis and allies variants