(Apologies for the poorly worded title, if someone can come up with a better one I'll change it)
So, despite what the schoolbooks say the outbreak of the American Revolution wasn't a sure thing; there were plenty of opportunities, before and after the war broke out, for the colonies to reconcile with Britain and become something like a proto-Dominion (the Albany Plan, the Carlisle Commission, etc.). Now, let's say for the sake of argument that somehow the Revolution is butterflied away, either through the adoption of the Albany Plan in 1754, or some kind of negotiated compromise during the war. How does this affect the abolition of slavery? Thanks to the efforts of people like William Wilberforce, the slave trade was abolished in 1807, with slavery itself being banned thirty years later. If, somehow, the Thirteen Colonies remain in the British Empire, will these changes still take place? Would the British abolition of slavery spark off (another) American Revolution, this one headed by the southern states?