This is your last position? You've gone from "Lincoln wanted to make slavery permanent" to this?
For the record, my position is that the south was indeed fighting for states rights, although the only states rights issue that had any traction with the southern populace was slavery, with, perhaps, tariffs a very distant second. Had there been no slavery in the south, I think the idea that there would have been secession and a civil war is absurd.
I think that slavery would have ended in the south eventually, without a civil war, although I think it would have taken at least until the middle of the 20th Century. Lincoln would have been quite content to limit it to the states where it already existed and prevent its expansion into new territories, secure in the knowledge that it would fade away in time. But, of course, once it became the cause of a Civil War, it had to be dealt with once and for all.
If Lincoln wanted to END slavery, he and the radical Republicans never would have allowed West Virginia to enter the union as a slave state.
Pure political expedience. In the end, slavery only lasted in West Virginia (and everywhere else) only four more years. Lincoln's admission of W.VA. as a slave state is much less an indication of his feelings on the Peculiar Institution than the Emancipation Proclamation and his advocacy of the 13th amendment, federal measures that did put an end to slavery.
I'll let Frederick Douglass have the last word:
"Had he put the abolition of slavery before the salvation of the Union, he would have inevitably driven from him a powerful class of the American people and rendered resistance to rebellion impossible. Viewed from the genuine abolition ground, Mr. Lincoln seemed tardy, cold, dull, and indifferent; but measuring him by the sentiment of his country, a sentiment he was bound as a statesman to consult, he was swift, zealous, radical, and determined. "
Assuming they did so, and no war occurred, would slavery have been permanent? You state that it would have lasted until the mid-20th century, almost another hundred years. How does extending it end it? Would allowing the states to continue abortion unfettered end it?
Had he put the abolition of slavery before the salvation of the Union, he would have inevitably driven from him a powerful class of the American people and rendered resistance to rebellion impossible.
Meaning it was not the aim of northerners. Lincoln himself favoured colonization/repatriation of blacks.
Viewed from the genuine abolition ground, Mr. Lincoln seemed tardy, cold, dull, and indifferent;
Again, Douglas notes that Lincoln was not an abolitionist.
... but measuring him by the sentiment of his country, a sentiment he was bound as a statesman to consult, he was swift, zealous, radical, and determined.
A sentiment for UNION. Much of the American industry relied on cheap Southern cotton, and few whites wanted to compete with blacks for jobs, especially the free-soilers. Restoring the union with slavery intact would accomplish both.
Lastly, tariffs were very important, enough that the Confederate Constitution prohibited tariffs designed to 'promote or foster any branch of industry', and also prohibited appropriations for 'any internal improvement intended to facilitate commerce' other than navigation (buoys, lighthouses etc). It was sink or swim economically. Even with slavery several northern states threated secession, since their industry lay in ruins due to the war of 1812. The Boston Tea Party was a riot over taxes, the Reagan Revolution was due to taxes.