I post this in response to a comment I received on the question of Lincoln's attitude toward slavery. The comment can be found under the blog entitled Future USA.
I have been a student of Lincoln most of my life, and I can tell you emphatically that he was anti-slavery. He felt that slavery was a sin morally, a crime legally, and a potential disaster economically and politically. The question was how best to deal with it. As a strictly legal matter, the South had the right to hold slaves; Lincoln thus argued, early in his career, for the right of the federal government and the states to limit the spread of slavery. His position, essentially, was that we (the anti-slavery forces and the central government) can do nothing about the slaves where they are, but we can stop slavery from spreading to other states and to the new territories. By doing so, we will both limit the evil, and condemn it to a slow death. He was consistent on this point all through his campaigns for the Senate and the presidency.
If by Lincoln being bi-partisan on the issue of slavery you mean that he was a relativist, that is not true. He opposed slavery, argued that it should be abandoned for moral and political reasons, and did what he felt it was constitutionally permitted to do to speed its demise. But up to the war, the Supreme Court had ruled in favor of the slavers' right to own slaves, and Lincoln, and all other elected officials, were obliged to abide by those rulings. Nonetheless, if you read the Cooper Union speech (and I urge you to do so), his most extended and profound pronouncement on the question of slavery, you will see that he understood that the South would never accept a compromise. He states clearly that it is not compromise that the South wants, since they had had many of them; rather, they wanted the North to agree with them that slavery was morally correct, and so should be allowed to exist and to spread. That is why he made the famous House Divided statement: the Union will be either all-slave or all-free, but it cannot go on as it is. The South clearly wanted the Union to embrace slavery and endorse it as a moral right, and with this, Lincoln says, the North could not agree.
He also makes it clear in that speech, through detailed argument, that the Founders overwhelmingly opposed slavery and believed that it would and should end eventually. He also mentions, interestingly, that the words slave and slavery never appear in the Constitution. His point is that the Founders accepted the fact of slavery in their deliberations on forming the Union, and knew that they could not secure the Union without acknowledging and compromising on the question.(This was the origin of the so-called three-fifths-of-a-man compromise, in which three-fifths of the slave population of the Southern states had to be counted in any census. It did not mean that the Founders considered slaves to be less than human; merely that members of the House should be apportioned with the acknowledgment that large parts of the Southern states' populations were black slaves. If this had not been done, the South, with its much smaller free population, would have had virtually no influence in Congress.) But Lincoln is persuasive on the point that the Founders neither approved of slavery, nor did they intend that it be a permanent part of the Union.
It is true that, initially, Lincoln did not forward the war as an anti-slavery struggle, though many in the North did. But Lincoln knew that the huge swell of volunteers who came forward to join the army in 1861 did not do so to eliminate slavery. Indeed, most of those boys had never seen a slave. Instead, they rallied to preserve the Union, and so Lincoln argued for the war initially as a pro-Union, not an anti-slavery, battle.
But by 1864, all that had changed. The emancipation was issued in the Fall of 1862, to take effect on the first day of 1863. By this act, Lincoln was making it clear that the cause of the North was two-fold: to preserve the Union and to end slavery. And he did this because he knew that the first could not be achieved without the second. As you may recall, in his famous letter to the abolitionist publisher Horace Greeley, Lincoln said that he "would save the Union," and if that meant he had to free all of the slaves he would do it, and if it meant that he must free none of the slaves, he would do it, and if it meant that he should free some of the slaves and leave the others as they were, he would do that. "But I would save the Union." (This letter was written before the emancipation was promulgated, though Lincoln had already made up his mind to it. And, in effect, he chose the last course: he freed some but not all of the slaves.)
Thus, he clearly saw abolition as a subset of the larger cause of preserving the Union, which he was bound by his oath of office to do. But in his own heart and mind, he was, and had long been, an opponent of slavery. It is not right, he said many times, that one man should earn his bread by the sweat of another man's brow, and he cited the Bible to this effect.
The Second Inaugural Address is his final statement on the relation between slavery and the war. In it he makes clear once and for all that the war was about slavery as much as about the Union; perhaps, as a moral matter, even more so. In fact, he puts the question in the largest moral context, arguing that God permitted slavery to exist in America as part of His inscrutable plan, and He now chose the eradicate it through this horrible war. It was not man's will but God's will that was behind the war and slavery, Lincoln says, and He now was using one to end the other. This was a courageous and nearly mystical view of the worst war of the nineteenth century, and Lincoln's way of somehow rationalizing it, and its terrible suffering, through submission to the will of God. (As I have said elsewhere in this site, if any modern president were to make such a statement, he would be hounded out of office forthwith.)
So to summarize: Lincoln was decidedly anti-slavery, though prior to the war, he tried to follow the law as it existed to that point. He was not one of the radical abolitionists, but he argued forcefully that slavery ought to be contained where it was, and not allowed to spread. He emancipated the slaves, technically, as a measure of war, which he had the legal right as Commander-in-Chief to do. Ironically, it was the South that gave him this right. You claim the slaves as your property, he argued, and so, as property of the enemy, I have the right to confiscate them and do with them what I think best to support our effort. And so he chose to free them. Though please note that, in another irony, the emancipation affected only those territories that were then in rebellion against the Union. Thus, the emancipation applied only to those slaves over which the federal government had no control. It specifically excluded slaves in states that had not joined the rebellion, such as Maryland and West Virginia, and parts of states which had already been secured by the Union Army, though Lincoln both urged their owners to free them, and offered to compensate them for doing so. But as the Union Army rolled through the South, it took the emancipation with it, and freed the slaves as it encountered them.
You say that Lincoln remains an important and enigmatic figure, perhaps for you alone. I assure you, you are not alone in this. His importance and the mysteries of his character remain an enigma to all of us who admire and study him.