Manifest destiny I believe first started in the mid 1840s, I think it appeared in US magazine and democratic review.
Answer:
The northerners thought that every person should have freedom, the southerners didn't believe that the slaves were people.
Explanation:
People in the north at the time believed that if not everyone was free, it wasn't actually a free nation. People in the south saw the slaves more as cash cows, and they thought that taking away the South's main source of income would cripple the American economy.
