This second global conflict resulted from the rise of totalitarian, militaristic regimes in Germany, Italy, and Japan, a phenomenon stemming in part from the Great Depression that swept over the world in the early 1930s and from the conditions created by the peace settlements (1919–20) following World War I.
After World War I, defeated Germany, disappointed Italy, and ambitious Japan were anxious to regain or increase their power; all three eventually adopted forms of dictatorship (see National Socialism and fascism) that made the state supreme and called for expansion at the expense of neighboring countries. These three countries also set themselves up as champions against Communism, thus gaining at least partial tolerance of their early actions from the more conservative groups in the Western democracies. Also important was a desire for peace on the part of the democracies, which resulted in their military unpreparedness. Finally, the League of Nations, weakened from the start by the defection of the United States, was unable to promote disarmament (see Disarmament Conference); moreover, the long economic depression sharpened national rivalries, increased fear and distrust, and made the masses susceptible to the promises of demagogues.
The failure of the League to stop the Second Sino-Japanese War in 1931 was followed by a rising crescendo of treaty violations and acts of aggression. Adolf Hitler, when he rose to power (1933) in Germany, recreated the German army and prepared it for a war of conquest; in 1936 he remilitarized the Rhineland. Benito Mussolini conquered (1935–36) Ethiopia for Italy; and from 1936 to 1939 the Spanish civil war raged, with Germany and Italy helping the fascist forces of Francisco Franco to victory. In Mar., 1938, Germany annexed Austria, and in Sept., 1938, the British and French policy of appeasement toward the Axis reached its height with the sacrifice of much of Czechoslovakia to Germany in the Munich Pact.
When Germany occupied (Mar., 1939) all of Czechoslovakia, and when Italy seized (Apr., 1939) Albania, Great Britain and France abandoned their policy of appeasement and set about creating an "antiaggression" front, which included alliances with Turkey, Greece, Romania, and Poland, and speeding rearmament. Germany and Italy signed (May, 1939) a full military alliance, and after the Soviet-German nonaggression pact (Aug., 1939) removed German fear of a possible two-front war, Germany was ready to launch an attack on Poland.
World War II began on Sept. 1, 1939, when Germany, without a declaration of war, invaded Poland. Britain and France declared war on Germany on Sept. 3, and all the members of the Commonwealth of Nations, except Ireland, rapidly followed suit. The fighting in Poland was brief. The German blitzkrieg, or lightning war, with its use of new techniques of mechanized and air warfare, crushed the Polish defenses, and the conquest was almost complete when Soviet forces entered (Sept. 17) E Poland. While this campaign ended with the partition of Poland and while the USSR defeated Finland in the Finnish-Russian War (1939–40), the British and the French spent an inactive winter behind the Maginot Line, content with blockading Germany by sea.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.