Answer:
It took the Emancipation Proclamation to make it happen
Step-by-step explanation:
The emancipation basically make slavery becomes illegal and force the southern states to conform unless they want to face punishments from the federal government.
In the past, slavery was really important to the southern states' economy because most of their production was done by using slave labor.
It is almost impossible for the southern states to willingly abolish slavery because they basically had to Crash their own economy in order to do that.
This is why we can make a generalization that It took the Emancipation Proclamation to make it happen. The northern states had to force the legislation to the southern states.