Answer:
Lincoln opposed the spread of slavery to the territories
Step-by-step explanation:
His Emancipation Proclamation paved the way for slavery’s abolition. Lincoln issued a preliminary Emancipation Proclamation, which took effect on January 1, 1863, and freed all of the slaves in the rebellious states not under federal control, but left those in the border states. He came to see emancipation as one of his greatest achievements, and would argue for the passage of a constitutional amendment outlawing slavery (eventually passed as the 13th Amendment after his death in 1865).