By 1865 the Emancipation Proclamation had the effect of eliminating all slavery in the USA. Lincoln further pushed the 13th amendment approval in the US House, personally ensuring 2/3rds majority vote. Lincoln was shot in the back and killed by one of those "southern gentlemen" before the states could ratify the 13th amendment, but clearly Lincoln was indeed fundamental in ending slavery in the US both in fact and in law.
THAT is a very debatable point. The Emancipation Proclamation freed no slave. It was a war measure. To quote A. Lincoln:
"If I could save the Union without freeing any slave I would do it, and if I could save it be freeing all the slaves I would do it; and if I could save it by freeing some and leaving others alone I would do that. What I do about slavery, and the colored race, I do because I believe it helps to save the Union, and what I forbear, I forbear because I do not believe it would help to save the Union."
Abraham Lincoln to Horace Greeley, 22 August 1862.