The US was a slave nation because of Massachusetts. They joined the six Southern states to vote for slavery because their bankers were making so much money off of the products slavery produced.
Just sayn . . .
Slavery was included in the United States Constitution because the original slave states voted to include it in the Constitution.
The original slave states were: New York, New Jersey, New Hampshire, Massachusetts, Connecticut, Delaware, Rhode Island, Pennsylvania, and Maryland.
North and South Carolina, Virginia, and Georgia were also slave states. Don't ever forget to cast four-thirteenth responsibility in that direction.