https://www.lib.niu.edu/2006/ih060934.html
From your article:
"Lincoln's March 16, 1861 letters to the governors did not endorse or oppose the proposed thirteenth amendment. "
From Lincoln's first inaugural address.
" I understand a proposed amendment to the Constitution--which amendment, however, I have not seen--has passed Congress, to the effect that the Federal Government shall never interfere with the domestic institutions of the States, including that of persons held to service. To avoid misconstruction of what I have said, I depart from my purpose not to speak of particular amendments so far as to say that, holding such a provision to now be implied constitutional law, I have no objection to its being made express and irrevocable. "
The chief proponent of the Corwin Amendment in the Senate was William Seward, who was also Lincoln's secretary of state. Seward guaranteed that New York would pass the amendment, and there is absolutely no possibility that Lincoln would have tolerated Seward working at cross purpose to him. Seward was doing Lincoln's bidding, and Lincoln was very much pushing for the Corwin amendment to be passed.
Tracking it back to it's origins, there are even some claims that Lincoln wrote the initial outline for it, and then pushed it through third parties to cover up his involvement in it.
Lincoln did not campaign for or seek the presidency to eliminate slavery, but to oppose its extension. That was the Republican position.
And why did Northern Liberals oppose the expansion of slavery? If you think they did so for moral reasons, I think you will be shocked to discover that the evidence indicates they did it only for reasons of gaining and holding on to money controlling power in Washington DC.
As for money vs. morality. Both principles often operate in concert. That fact doesn’t negate the truth. If you want “pure as the driven snow”, in politics, as in life, you will be sorely disappointed.
The profits of slavery flowed North as well as benefited the planter class in the South. Yet Northern states began its abolition, the South refused all compromise and reaped the whirlwind.
The same is now coming due for the haters that infest the left and control the Democrat (slaver) party.