Background

World War I radically altered the political map, with the defeat of the Central Powers, including Austria-Hungary, Germany and the Ottoman Empire; and the 1917 Bolshevik seizure of power in Russia. Meanwhile, existing victorious Allies such as France, Belgium, Italy, Greece and Romania gained territories, while new states were created out of the collapse of Austria-Hungary and the Russian and Ottoman Empires. Despite the pacific movement in the aftermath of the war,[10][11] the losses still caused irredentist and revanchist nationalism to become important in a number of European states. Irredentism and revanchism were strong in Germany because of the significant territorial, colonial, and financial losses incurred by the Treaty of Versailles. Under the treaty, Germany lost around 13 percent of its home territory and all of its overseas colonies, while German annexation of other states was prohibited, reparations were imposed, and limits were placed on the size and capability of the country's armed forces.[12] Meanwhile, the Russian Civil War had led to the creation of the Soviet Union.[13] The German Empire was dissolved in the German Revolution of 1918–1919, and a democratic government, later known as the Weimar Republic, was created. The interwar period saw strife between supporters of the new republic and hardline opponents on both the right and left. Although Italy as an Entente ally made some territorial gains, Italian nationalists were angered that the promises made by Britain and France to secure Italian entrance into the war were not fulfilled with the peace settlement. From 1922 to 1925, the Fascist movement led by Benito Mussolini seized power in Italy with a nationalist, totalitarian, and class collaborationist agenda that abolished representative democracy, repressed socialist, left wing and liberal forces, and pursued an aggressive foreign policy aimed at forcefully forging Italy as a world power—a "New Roman Empire".[14] In Germany, the Nazi Party led by Adolf Hitler sought to establish a fascist government in Germany. With the onset of the Great Depression, domestic support for the Nazis rose and, in 1933, Hitler was appointed Chancellor of Germany. In the aftermath of the Reichstag fire, Hitler created a totalitarian single-party state led by the Nazis.[15] The Kuomintang (KMT) party in China launched a unification campaig against regional warlords and nominally unified China in the mid-1920s, but was soon embroiled in a civil war against its former Chinese communist allies.[16] In 1931, an increasingly militaristic Japanese Empire, which had long sought influence in China[17] as the first step of what its government saw as the country's right to rule Asia, used the Mukden Incident as a pretext to launch an invasion of Manchuria and establish the puppet state of Manchukuo.[18] Too weak to resist Japan, China appealed to the League of Nations for help. Japan withdrew from the League of Nations after being condemned for its incursion into Manchuria. The two nations then fought several battles, in Shanghai, Rehe and Hebei, until the Tanggu Truce was signed in 1933. Thereafter, Chinese volunteer forces continued the resistance to Japanese aggression in Manchuria, and Chahar and Suiyuan.[19] Benito Mussolini (left) and Adolf Hitler (right) Adolf Hitler, after an unsuccessful attempt to overthrow the German government in 1923, became the Chancellor of Germany in 1933. He abolished democracy, espousing a radical, racially motivated revision of the world order, and soon began a massive rearmament campaign.[20] Meanwhile, France, to secure its alliance, allowed Italy a free hand in Ethiopia, which Italy desired as a colonial possession. The situation was aggravated in early 1935 when the Territory of the Saar Basin was legally reunited with Germany and Hitler repudiated the Treaty of Versailles, accelerated his rearmament programme and introduced conscription.[21] Hoping to contain Germany, the United Kingdom, France and Italy formed the Stresa Front. The Soviet Union, concerned due to Germany's goals of capturing vast areas of eastern Europe, wrote a treaty of mutual assistance with France. Before taking effect though, the Franco-Soviet pact was required to go through the bureaucracy of the League of Nations, which rendered it essentially toothless.[22][23] However, in June 1935, the United Kingdom made an independent naval agreement with Germany, easing prior restrictions. The United States, concerned with events in Europe and Asia, passed the Neutrality Act in August.[24] In October, Italy invaded Ethiopia, and Germany was the only major European nation to support the invasion. Italy subsequently dropped its objections to Germany's goal of absorbing Austria.