The 1929 American stock market crash triggered a Great Depression, which caused the international economy to collapse and affected millions worldwide. Western democracies expanded their powers and responded with relief programs. Authoritarian and Fascist regimes arose to replace some capitalist democracies, which many perceived as outdated. Only World War II ended the depression.

The radical totalitarian dictatorships of the 1920s and 1930s were repressive, profoundly anti liberal, and exceedingly violent. Mussolini set up the first Fascist government, a one-party dictatorship, but it was never truly a totalitarian state on the order of Hitler’s Germany or Stalin’s Soviet Union.

In the Soviet Union Stalin launched a socialist “revolution from above,” to modernize and industrialize the U.S.S.R. He set staggering industrial and agricultural goals and replaced private lands with (often forced) collectivization. Mass purges of the Communist Party in the 1930s, leading to the imprisonment and deaths of millions, allowed Stalin to replenish the Communist Party with young loyalists.

Hitler and the Nazi elite rallied support by recalling the humiliation of World War I and the terms of the Versailles treaty, condemning Germany’s leaders, building on racist prejudices against “inferior” peoples, and warning of a vast Jewish conspiracy to harm Germany and the German race. The Great Depression caused German voters to turn to Hitler for relief. After he declared the Versailles treaty disarmament clause null and void, British and French leaders tried appeasement. On September 1, 1939, his unprovoked attack on Poland forced the Allies to declare war, starting World War II.

Nazi armies first seized Poland and Germany’s western neighbors and then turned east. Here Hitler planned to build a New Order based on racial imperialism over the Jews, Slavic peoples, and others. In the Holocaust that followed, millions of Jews and other “undesirables” were systematically exterminated. In Asia the Japanese created the Greater East Asian Co-Prosperity Sphere. This was a sham, as “Asia for the Asians” meant nothing but Japanese domination and control. After Japan attacked Pearl Harbor, the United States entered the war. In 1945 the Grand Alliance of the United States, Britain, and the Soviet Union defeated the outproduced and outmanned Germans and Japanese.