American civil war was fought between the US army of the North led by US president Abraham Lincoln and Confederacy in South on the issue of Slavery.
Technically, the Korean war is still on as there was never a final end of war peace agreement, but just a temporary armistice was signed.
The “Monroe doctrine” was a foreign policy initiative by President James Monroe of United States in 1823. Since then, for a century, US’s foreign policy more or less followed the path set by the Monroe doctrine.
Spanish civil war happened just before the start of WW2, from 1936 to 1939. It was fought between the Republicans, who were loyal to the democratic, left-leaning Second Spanish Republic, and the Nationalists, a falangist(a form of fascism) group led by General Francisco Franco who ruled Spain from 1930 to 1975 as its dictator.
Italy under Mussolini had joined with Nazi Germany and Japan to form the Axis powers. He adopted fascism led his country in to another world war.
Ironically, In 1922, the King himself invited Benito Mussolini into government.
Hitler capitalized on the prevailing socio-economic and political factors prevailing in post-war Germany to become one of history’s most influential dictator. The most fascinating thing is that Hitler gained power at least initially through democratic process when he became the chancellor of Germany in 1933 and later assumed the title of ‘Fuhrer'(The leader) and ruled the Third Reich(Nazi Germany) from 1934 till his death in 1945.
There are multi-dimensional factors that led to this phenomenon: