Well, Up With the Star produced a nuclear WWII between Tsarist Russia, Fascist Italy, the Republic of China and associated puppet-states against Imperial Germany, Imperial Japan, the Dutch, Belgian, and British Empires and the United States of America, a war that sees Russia starting with a much more economically and technologically advanced basis for the war as well as the Ottoman Empire poised to become one of the great cultural and economic engines of postwar Europe, while South America is the most pristine continent in the postwar world.
All this from Benjamin Butler accepting Abraham Lincoln's offer to be Vice President, leading to David Hunter taking his place as commander of the Army of the James in May 1864.