Had Canada (excluding Rupert's Land) joined the Revolutionary War along with the 13 other colonies, and experienced the same OTL victory, what would the impact have been on Slavery?
The way I see it, Jefferson's 1784 proviso on banning slavery in the West would likely come to pass with more immediate effect (failing by one vote OTL), and that likely means that Kentucky and Tennessee are not slave states. Could gradual emancipation then occur in states like Virginia, Maryland, and Delaware? What if, on an unrelated POD, Georgia ends up free as it was until 1749?
How would these changes and new States impact slavery in America?