It was actually started to abolish slavery. It was the reason for its founding.
The early Republican Party platform was to stop the expansion of slavery, not abolish it.
At least that is the way President Lincoln explained it.
The Democrat state of Georgia actually cast the decisive vote ratifying the 13th amendment.
Which makes it very strange that they voted for an Amendment to the Constitution to make slavery permanent.
The Corwin Amendment passed the House (controlled by Republicans) by a 2/3rds margin in March of 1861, then it passed the Senate (Controlled by Republicans) by a 2/3rds margin a short time later.
First Republican President Lincoln called for the Amendment to be passed by the States in his first inaugural address.
Funny Republicans who voted for slavery. Why it's almost as if they were lying about what they wanted.