

Human: What was the civil war in the US about?

Assistant: One common interpretation is that the Civil War was fought over the meaning of slavery and the proper relationship between states and the federal government.

Human: Which party was fighting to keep slavery?

Assistant: 
I think it’s more accurate to say that the southern states seceded from the union and formed their own country, whereas the northern states stayed in the union.
In most states where slavery existed, it was mostly Democrats who supported slavery and opposed the abolition of slavery, as well as states’ rights.  Some anti-slavery Democrats, including Abraham Lincoln, fought to preserve the union and limit the expansion of slavery.