The so what is his statement was correct. Lincoln added a state (unconstitutionally) which allowed slavery. This is yet another piece of evidence to show that abolishing slavery was not Lincoln's motivation - if his orchestration of the passage of the Corwin Amendment through Congress and its ratification by multiple states as well as his public promises to strengthen fugitive slave laws were not enough evidence that abolishing slavery was not really what he was after.
Oh, is that what jeffersondem was trying to prove?
Was this even up to debate?! I had thought that it was generally well known that Lincoln himself had said,
"If I could save the Union without freeing any slave I would do it, and if I could save it by freeing all the slaves I would do it; and if I could save it by freeing some and leaving others alone I would also do that."
Lincoln wanted first to save the Union; he knew that only then would it be possible to also free the slaves.
Obviously: Losing the war / allowing the South to secede would preclude freeing all of the slaves.
Regards,