"“You know, the Civil War, you think about it, why?” Trump said. “People don’t ask that question, but why was there the Civil War? Why could that one not have been worked out?”"
This has come up on Newsvine before.
It was concluded that it wasn't about slavery (which was bought from an existent Trade in Africa, and also already included other races). It was about economics--what was cheaper for that area to manage and produce products. The south used people; the north used machines. ...the basis of the fight - profit.