The best answer is, to the rise of totalitarian regimes in some countries.
A surge of totalitarianism could be expected in some European states following the political, social, and economic chaos of World War I and the Great Depression. Totalitarian regimes flourished in countries where fascism and communism were popular, including Germany, Italy, and the Russian Empire. Many leaders used the state's total control of economy and society associated with totalitarianism to address issues of their time which included job shortages, insufficient industry, or even foodstuffs depending on the region.
In general, the widespread use and availability of electrical power and family-owned cars increased the work force by offering more incentives to work. More jobs were also available during this time.
The Emancipation Proclamation is very important to the United States because it abolished slavery. The Emancipation Proclamation was a executive order, ordered by President Abraham Lincoln, on January 1, 1863 that abolished slavery completely. This executive order changed the topic of the war to freeing slaves and bringing them to the free land. If it wasn't for this executive order, there could possibly still been slavery during their time, and possible today.