OK, so you are not an adherent to the “rule of law?
The Declaration of Independence seemed to not advocate the then current rule of law. Am I missing something there ?
“All laws which are repugnant to the Constitution are null and void.” Marbury vs. Madison
Slavery was 100% constitutional and a most evil thing. Based on your logic Abraham Lincoln should have just looked the other way and said, "slavery is okay."
He did not and actually acted in an unconstitutional manner. Was he wrong based on your logic?
In reality Lincoln should have approached this via constitutional amendment before the war. If he did such the greatest loss in war of American lives would have not happened. If one looks at the population of the United States then as compared to today the percentage of losses by both side union and confederate were horrific.
Oddly Lincoln was rather racist and considered negros inferior though he abhorred slavery. Cut and past the link below about Lincoln and trying to send free slaves back to Liberia.
https://psmag.com/news/remember-that-time-abraham-lincoln-tried-to-get-the-slaves-to-leave-america-55802
Lincoln was no hero. Lincoln did preserve The Union and this is the only damn thing he did of merit.
ps Arlington Cemetery was the old home and plantation of Robert E Lee. It was chosen as a burial ground for Union Soldiers during the Civil War. Today Union Soldiers and Confederate Soldier lay in the same ground by choice. Once again brothers in arms. It is sacred ground