My dad and I came up with this one while visiting a few Civil War battlefields, and I thought that I'd get some input here.
The starting point in our outline is that Abraham Lincoln loses the election of 1860, and Breckenridge (the Southern Democrat) becomes President. One possibility is that the Democrats managed to avoid splitting, so Douglas isn't in the race. Anyway, we now have a pro-slavery Southern Democrat in the White House.
Obviously, the Civil War doesn't start immediately. But over the next few years, tensions continue to build. The combined effect of the Dred Scott Decision and the Fugitive Slavery Law is to emasculate the Northern states' own anti-slavery laws. Many in the North, recalling Lincoln's words that "this nation cannot endure half slave and half free" fear that President Breckenridge's answer is that it will be all slave.
We haven't figured out the trigger, but by 1864 or 1865, the Northern free states begin to secede. The South decides to let them go. At first, it seems as if the breakup of the Union will be peaceful. The free states form the Federated States of America (also known as the Federation), with their capital at New York City, and the Federal constitution forbids slavery.
But then there becomes the question of the western territories. California and Oregon have joined the Federation, but there is no decision on the subject of the territories. Breckenridge may not want to force the Northern states to stay, but he doesn't want to lose the territories. He sends troops out to secure them, and ensure that when those territories seek statehood, they will be slave states, and remain in the Union. In response, California sends out its own troops to protect the territories, prevent the Federation from being split in two, and push as many of them into the Federal camp as possible.
The result is Bleeding Kansas writ large. Troops from both sides stream West. It isn't immediate, but soon the Union and the Federation are at war. And sooner or later, one side or the other decides that the way to victory isn't to send more men out west, but instead to hammer the east.
A few questions:
- What could trigger the Northern Secession?
- What would happen to the Navy? One idea I've had is that with the peaceful secession, the Northern sailors (ie most of them) simply go home. The Union is left with an intact navy, but a lot of empty or shorthanded ships. They could easily replace them, but the new crews will be inexperienced. The Federation, on the other hand, has essentially no Navy to start with, but has a corps of experienced sailors, and the ability to build a new Navy.
- Would the British and French get involved? Which side would they take?
- And the biggest question of them all: who wins the war, and will the victor seek to destroy the loser?