The Civil War & Lincoln
Of course, some folks think this would have been a good outcome, but it is likely that a Confederate nation would have continued to fight against the United States for control of the western territories. In other words, a negotiated peace would not have led to peace. Besides, the slave empire would have turned its attention south to Mexico and the Caribbean.
By the way, aren't the names of those rivers in Georgia cool? Oostanaula, Etowah, and of course, Chattahoochee, brought to the attention of non-Georgians by Alan Jackson. Cherokee names, no?