Let me begin by saying that the title of this post is one of the most-asked questions about the Civil War/Reconstruction era. Let me add that the answers usually tell me far more about the perspectives and opinions of the person asking the question than about Lincoln.
First, having stipulated that the real answer is “We don’t know,” let’s set that aside. Instead, let’s recall that Lincoln himself wasn’t sure. He said as much during his last cabinet meeting, in which he recognized that with the war coming to an end (like others, he saw Lee’s surrender to Grant as marking that transition), the policies he had framed in response to wartime priorities might no longer be best suited to coming circumstances. Thus it would be a mistake to project wartime policies on the postwar situation, because Lincoln recognized the need for change.
Moreover, usually the question of “what if Lincoln had lived?” becomes “how would Lincoln have worked with the (supposedly radical-controlled) Congress?” This discussion quickly becomes problematic. First, scholars have shown that the radicals did not have the upper hand, period. They viewed what emerged in 1866 and 1867 as a set of compromises and concessions. Second, even those policies were in large part a response to the events of 1865 and 1866, including black codes, race riots, white southern intransigence, and so on … all which in real life was largely condoned by Lincoln’s successor, Andrew Johnson. So, if Lincoln lives, the more historically accurate question would be how he would have dealt with the behavior of former Confederates in 1865 and 1866. I don’t see Lincoln putting up with such recalcitrance, and he certainly would not have condoned what happened at Memphis or New Orleans, and he certainly would not have tolerated the KKK … all of which happened prior to the framing, let alone passage, of the Reconstruction Acts. What apologists for southern white supremacist terrorism claim was a reaction to the policies of congressional Republicans in fact preceded those measures.
When it came to African Americans, indeed, by 1865 Lincoln was in a different place than he had been in 1862 (recent claims to the contrary notwithstanding). Lincoln had been looking for a limited place for blacks in the postwar political order privately in 1864 and publicly in 1865. Whatever remained of any sentiment for colonization was at best an effort to offer freedpeople an option, not a mandate or preferred policy. African Americans would be part of the postwar polity, and Lincoln knew it, even embraced it. The presence of blacks in Union ranks had helped move him in that direction; part of the result was his willingness to sign the Freedmen’s Bureau Bill on March 3, 1865, just twenty-four hours before he spoke of “malice toward none (including black people) and charity for all (including black people).” That’s right, “none” and “all” are not simply former Confederates–that’s an implication made by others who believe that Lincoln would have been so in favor of reconciliation that he would have resembled a kinder, gentler Andrew Johnson.
I doubt Lincoln would have followed that path. Only a year before he had spoken about retribution for what had happened at Fort Pillow, although he abandoned it as impolitic. The idea that he would have signed the Freedmen’s Bureau Bill and then attempted to destroy the bureau, as Johnson tried to do, is ludicrous. The idea that he would have tolerated white supremacist violence is equally ridiculous. With Congress not in session until December, maybe the real question is what would the white South have done had Lincoln lived … and what would Lincoln have done had the white South behaved as it did with Andrew Johnson as president. For, had white southerners acted differently in 1865 and 1866, congressional Republicans would have faced a different political terrain as they embarked upon proposing legislation. Everything else changes.
It always astonishes me that so many people deprive white southerners of historical agency in 1865-66. Yet their actions in 1865 and 1866 (as well as the behavior of Andrew Johnson) did much to shape what was to follow. To assume that Abraham Lincoln would have tolerates white southern behavior as Andrew Johnson did does such violence to the historical record as to render serious discussion moot.