“That’s not true.”
But, it is. As a young Congressman Lincoln had no problem with the idea of secession, and he said that all that was needed was the will and the power to bring it about. Perhaps he was saying that secession was okay as long as one can pull it off. In which case, the Confederate states were fully within their rights to secede (according to Lincoln’s logic), BUT ONLY AS LONG AS THEY WERE NOT FORCED BACK IN!
But it is not. Lincoln was talking about rebellion, not secession. There is a difference between the two.