April 1865. John Wilkes Booth enters Lincoln box at Ford's theater and shoots Lincoln... ...and misses. Somebody jostles him or he just flat bungles the act, maybe shooting off Lincoln's ear but Lincoln survives. How does history in Lincoln's second term play out?
Andrew Johnson never becomes president and the mistakes he made never happen. Nevertheless, it's hard to imagine Lincoln escaping assassination. If Booth had missed then some other disgruntled Confederate would have shot him later.
At the end of the Civil War, there was a strong countercurrent in the GOP which wanted to repatriate all the emancipated slaves (less than a million) to Monrovia. The politics were lining up with Congressmen from the Old Northwest (OH,IN, IL, WI, MN, MI, and Iowa) along with loyal border states (MO, KY, MD, and DE) coalescing around Lincoln favoring repatriation versus the "Radicals" fro New England and New York who wanted citizenship for emancipated slaves. Lincoln liked repatriation for two reasons. First it removed a major irritant for the erstwhile Confederacy, which Lincoln wanted to re-incorporate into the US as quickly as possible. Second, he knew the two races would not get over slavery for generations. Better to send the emancipated slaves back than endure the trouble. When Lincoln died the nascent western/southern coalition evaporated, the Radicals prevailed, and the rest is history. Just a nudge on Booth's elbow...