Well, Lincoln's plan for Reconsruction, though it hardened over time, was quite modest compared ot the one acually passed-that was the Radical Republican plan, which Lincln quarreled with in his life and was passed after his martyrdom. Definately an earlier 15th Amendment, in time to elect a Republican in 1868. As said, the coaliion may, with luck, last longer, and secure a freer South.
The big issue here is Reconstruction. Lincoln's plan was certainly more lenient. However, one must take into account that I believe that plan was from 1863, and Lincoln did change quite a bit over his presidency to a more protective and friendly opinion of blacks. There was a sort of social contract between North and South in a lenient reconstruction; we get you back into the Union quickly and all is forgiven, and you given blacks in your region equality and protect that. The problem being that, if I recall correctly, the Southern aristocracy saw fit to reassert its power and the South did its damnedest to prevent black equality through every means possible.
So while a more lenient reconstruction could avoid harsh backlash which would create Jim Crow, it could also create close to the same thing from the get go. Something else I recall is Lincoln wanting to educate the slaves before giving them voting rights or something of that nature.
The aristocracy were by and large the ones who controlled things in the South.Why single out the aristocracy?
It's not just about that basic problem where it concerns social opinion of black equality, but what is done in addressing it. Radical Reconstruction helped black equality, but alienated Southern whites and drew backlash which angrily reasserted inequality and worse; then again, from what I can recall when the lenient plan was in action during early reconstruction, Southerners started slipping the chains back on again anyway. So to get reconstruction to work, a political tight rope needs to be walked between those two extremes which Lincoln, having evolved over the course of the war, seeing the South not live up to its end of the bargain (equality of the South with the rest of the Union in exchange for equality of blacks with whites), not being as brash as Johnson (and thus alienating Congress) and ever the statesmen, may be able to walk. But what he would actually do is something I don't know.Basic trouble. The Southern Whites care, deeply, about keeping the Blacks in their place. Northern whites don't, by and large, care all that much about helping them out of it - or at least it isn't a high priority.
With all due respect to Mr Lincoln, I don't see how keeping him around removes that basic problem.
The aristocracy were by and large the ones who controlled things in the South.
You can't force morality on a people's soul. You can't change people's minds forcibly. But, taking a lesson from Civil Rights about a century later, that wasn't the point; it was that even if they didn't like blacks and didn't view them as equals, they were still going to treat them equally because of the law of the land which was going to be enforced. That's not impossible given what happened in the 1950's and 60's.
No doubt, but what of it?
When they lost power to the poorer whites, that did nothing whatsoever for the Blacks. If anything they got treated worse. So weakening the aristocracy won't help on that point - or at least there's no obvious reason why it should.
Prohibition was the law of the land too. It failed just the same.
Saying "It's the law of the land" counts for nothing unless the will to enforce it exists - and in the 19C (and half of the 20C) it did not. Even a President as powerful as FDR never thought the issue worth raising.
In the second half of the 20C it did exist - because the Cold War made the Southern racial setup an intolerable handicap in competing with the Commies for Third World support. Add to that the breakdown of the old economic system due to mechanisation of agriculture - the South didn't need cotton-pickers like it used to - and the fact that since the Great Depression, the states, and especially poorer ones like those in the South, had become increasingly reliant on Federal contracts and suchlike. Their Governors might occasionally grandstand it in schoolhouse doors, but that was little more than a small child throwing a tantrum. The Southern States were economically dependant on Uncle Sam, and could not defy him in any serious way.
A century before, the government had none of those levers. All it had was a small army, which could hang around in the South, making (from the Southern pov) a nuisance of itself, until northern voters got fed up and it was recalled. That remains true whoever is in the White House, and pretty much whatever he does.
Reverting to Mr Lincoln, keep in mind that whatever his sympathy for the Freedmen, his top priority is and always has been restoring the Union, which primarily means reconciling the defeated Southern Whites to it. Black rights, at the end of the day, can only be the second priority, not the first. How did Frederick Douglass put it? "You whites are Lincoln's children. We negroes can be, at best, his stepchildren". Douglass was surely right.
With respect to obeying the law of the land: One of the really scary scenes in Arthur Haley's novel "Hotel" is where the protagonist is in deep, DEEP trouble for renting a hotel room to a black man DESPITE the fact that it was not only the MORAL thing to do, but the LEGAL one. It (basically) takes deus ex machina to keep him from being fired. NB: he was to be fired for OBEYING THE LAW!
My mind just totally boggled at that scene.