The Origins of World War II

In 1941, two major alliances squared off against each other. Japan, Germany, and Italy, along with their conquered territories, formed the Axis powers, the name of the alignment between Nazi Germany and Fascist Italy that had been formed in October 1936. The term was used later to include Germany's other allies in World War II, especially in Japan. The Allied powers included France and its empire; and Commonwealth allies (such as Canada, Australia, and New Zealand); the Soviet Union; China; and the United States and its allies in Latin America.

The construction of these grand global alliances took place over the course of the 1930s and early 1940s. Driven in part by a desire to revise the peace settlements that followed the Great War and compelled by the economic distress of the worldwide depression, Japan, Italy, and Germany engaged in a campaign of territorial expansion that ultimately broke apart the structure of international cooperation that had kept the world from violence in the 1920s. These revisionist powers, so called because they revised or overthrew the terms of the post- Great War peace, confronted nations that were committed to the international system and to the avoidance of another world war. To expand their global influence, the revisionist nations remilitarized and conquered territories they deemed central to their needs and to the spread of their imperial control. The Allies acquiesced to the revisionist powers' early aggressive actions, but by the late 1930s and early 1940s the Allies decided to engage the Axis powers in total war.

The global conflict opened with Japan's attacks on China in the 1930s: the conquest of Manchuria between 1931 and 1932 was the first step in the revisionist process of expansionism and aggression. Within Japan a battle continued between supporters and opponents of the aggressive policies adopted in Manchuria, but during the course of the 1930s the militarist position dominated, and for the most part civilians lost control of the government and the military. In 1933, after the League of Nations condemned its actions in Manchuria, Japan withdrew from the league and followed an ultranationalist and promilitary policy. Seeing territorial control as essential to its survival, Japan launched a full-scale invasion of China in 1937. A battle between Chinese and Japanese troops at the Marco Polo Bridge in Beijing in July 1937 was the opening move in Japan's undeclared war against China. Japanese troops took Beijing and then moved south toward Shanghai and Nanjing, the capital of China. Japanese naval and air forces bombed Shanghai, killing thousands of civilians, and secured it as a landing area for armies bound for Nanjing. By December 1937 Shanghai and Nanjing had fallen, and during the following six months Japanese forces won repeated victories.