Technology is probably the answer that you need. Other answers such as internet, cell phones, and airplanes are suitable answers as well.
The federal government was too weak, and couldn't enforce their laws. They had borrowed money for the Revolutionary War and couldn't pay their debt. They also lacked the power to tax.
Therefore, the answer would be the first one.
I believe they were set up as places for religious freedom (though Massachusetts turned into a place where only Puritans could be in charge and practice their beliefs.)
Hope this helps! Please let me know if I'm wrong. :)
Answer:
I would say slavery divided them.
Explanation:
Slavery was a big deal to the North and they didnt like it but it was the way the South ran and how they functioned. Hope this helps