Point of order. They did not invade the South to stamp out slavery. They invaded the South to stop it from gaining independence from Washington's control.
Lincoln fully intended to keep slavery when he sent the troops to stop the South's Independence movement.
Lincoln hated slavery, and was an abolitionist. Douglas advocated slavery. You might find the Lincoln-Douglas debates an interesting read. However, Lincoln did say he would accept slavery if it would keep the union together but that is not the same thing as supporting it. However, he also strongly believed this country was weakened by slavery (just as our nation is weakened today by outsourcing our industrial base to slave-like countries such as China, and our professional jobs to impoverished countries such as India.) If the south had been allowed to leave the union it soon would have soon been under the English Queen (Victoria) as it did not have the industrial base to defend itself against the might of the British empire. And with the fall of the south to English rule, the north might have fallen as well even though it was much richer. There was much more at stake than just ending slavery, the country was divided and falling apart. Lincoln did some things that we condemn him for them but we should not, there was much at stake. I fear that Pres. Trump is going to make compromises and do some things that we are not going to like in an effort to keep this country together as we are under assault in so many ways. It is going to be difficult to save this country. I hope that he can do it but I am not sure we can be saved. But maybe God has other plans, and will give us one last victory over the evils we face, before the end comes. Anyway, I hope so.