Calling Lincoln anti-slavery is being a bit generous. Before the war he was against the *expansion* of slavery (with the end of perhaps abolishing it eventually) and once the war broke out he was primarily concerned with saving the Union, even if it meant preserving slavery. Initially he didn't even allow his generals to free slaves in captured territories. He didn't start to free the slaves in the South (with the Emancipation Proclamation) until the war was going pretty badly for him and he needed some momentum.

He did make it clear that ethically he did support the suffrage of slaves, though.

http://en.wikipedia.org/wiki/Abraham_Lincoln_on_slavery