1
Not only did Lincoln run on a platform of a complete outlawing of slavery in the territories which would necessarily lead to total abolition, but in his very first speech as a political candidate running for a federal office he explicitly insisted that the nation must make a choice between being entirely free or entirely slave. Since he clearly sided with being entirely free, he was announcing loud and clear to the entire nation that his political goal was to eliminate slavery everywhere. That's why the South seceded before he even took office as president, because they knew that his election meant slavery in the South was doomed.