disapproved of slavery on a personal basis and felt compellted to describe his opposition to it on moral, ethical, and even legal grounds on a consistent, ongoing basis throughout his life leading up to his Presidential run (when political pressures stayed his tongue where they previously would not have done so).
I think it is indisputable to claim that Lincoln wished to live in a country (and world!) where slavery was no longer practiced. Ditto Thomas Jefferson (which is, perhaps, the only meaningful overlap to be found in these two mens' public personae). Any assertion to the contrary is a poorly-conceived one in my estimation; we've got piles of letters and transcripts of speeches where Lincoln makes clear his personal and moral/ethical/ideological opposition to slavery.
Where I take issue with the historical presentation of Lincoln is where it comes to his political will and aims when it came to slavery. I don't post on this subject without including some variant of the following: If Lincoln had declared without reservation prior to the Civil War's engagement that he aimed to free the slaves, by force if necessary, I would find little or no fault in his conduct prior to, during, and after the Civil War.
Declaring the end of such an evil institution to be his primary goal, and doing so with the threat of force (unnecessary, as Britain demonstrated, but a meaningful and important gesture to be sure!) would have planted him in reality precisely where the history books attempt to paint him. But the letter to Greeley is, in my view, the final nail in the coffin against the suggestion that his goal was to free the slaves or end the institution of slavery. Ending slavery was a byproduct of his other goals (whatever they were--I really don't much care, though I could be compelled to care by a convicing argument), and I think we do ourselves a disservice by insisting, as a society that looks to me like one with fingers stubbornly jammed in its own ears, that Honest Abe's most considered words on the matter are not indicative of his true motives.
He said his aim was to preserve the Union, not end slavery. The two were interconnected, yes, but I'm going to take the direct source on this one--unless we're beginning the conversation by saying that we can't trust what Lincoln said on this all-important matter, in which case...what are we even talking about?