I would say because they needed props for the civil war. So they started to slave people and make lots of food. But the biggest was the balance of power in the federal government.
The North was industilsizing and the South was relying on slaves to make a living. The South is mad about their slaves escaping in the Underground Railroad. By 1861, Lincoln was made president and The South thought he was going to take their slaves away so they wanted to secede.
