As an Irish person I have a limited knowledge of the man but to further the conversation track id like to add that his ending of Slavery was very much politically motivated. The South was starting to gain international recognition as a separate entity (France and Britain wanted to trade for Cotton which the south was the largest producer of at the time).
Lincoln abolished slavery as a political maneuver which turned the tables and placed slavery at the apex of the entire argument. Britain and France could not been seen to support the south as this would have been viewed as supporting slavery by their populace, an extremely unpopular position in Europe. So we can throw that into the mix I guess, only abolished slavery as a self serving move... For reference I think the guy was pretty decent :)