As usual, the facts don't follow the progressive agenda, expecially historical facts.
Lincoln supported the Corwin Amendment which would have protected slavery in the states that it already existed in. Here is a link to facts about Lincoln and the Corwin Amendment:
Lincoln and the Corwin Amendment « Crossroads
Of particular interest is this quote by Lincoln:
"Do the people of the South really entertain fears that a Republican administration would, directly or indirectly, interfere with their slaves, or with them, about their slaves? If they do, I wish to assure you, as once a friend, and still, I hope, not an enemy, that there is no cause for such fears. The South would be in no more danger in this respect than it was in the days of Washington. I suppose, however, this does not meet the case. You think slavery is right and should be extended; while we think slavery is wrong and ought to be restricted. That I suppose is the rub. It certainly is the only substantial difference between us."