Lincoln showed us an example of what it's like to be presidential. No single issue is more important then the nation.
Before I read Walter Williams thoughts I'm gonna say that it doesn't matter what someone else thinks. It's what Lincoln thought that matters. Or are you trying to say that Williams could read his mind years after his death? Lincoln's comments were about what was his primary concerns not that he didn't care about slavery.
We seem to be arguing for the sake of arguing here.
I've made my point. You can keep yours if you want...but a floating argument isn't gonna prove you're right.
When it came to the Civil War, I don't Believe he did Care about Slavery... You, myself nor Walter Williams will EVER Know, but I can Quote Lincoln Justifying the Civil War with his at best Nuetral Stance on Slavery at THAT time...
What he did with the Political Capital he had after the War is another Debate.

peace...
This is my simple opinion, and anyone can accept it, reject it, or modify it. I do believe he did abhorred slavery as an institution that harmed the Union. He also believed that it was constitutionally protected. More than a year and a half passed after Ft Sumter before he moved decisively on the issue. I believe he had come to the conclusion that the institution had to be destroyed in order to make a better America after the war.
As an aside: Walt (with whom I have chatted by email a few times over the last fifteen years) cracks me up about race and slavery. In part because he considers John C. Calhoun one of America's great politicians. This from a man whom would only have been allowed by John C. to push a broom in a newspaper office.
Takes all kinds.