POD: Robert Anderson never moves his forces into Fort Sumter and instead issues a fallback to Union territory, therefore no war erupts due to this. Although the media in the south describes it as a grand victory, the Confederacy is not much without Virginia, which in OTL joined the Confederacy after the Battle of Fort Sumter. Lincoln declares that slave-holding nations in the Union had the right to have slaves but they would be set free if ever seen with his/her owner in a non-slavery state. In 1920 Boll Weevils managed to ruin thousands of cotton plantations in the south. This event led to the destruction of slavery in the Union and a large depression in the Confederacy. The Confederacy in World War I would help the Entente win while also helping the Allies in World War II. The United States would continue to isolate itself from the world, meaning no Marshall plan and a devastated Asia and Europe. It's strange how small things destroy the world so quickly with a Failed Confederation...
See also: Timeline
(I'm busy at the moment with other things, but I promise to continue this article.)