What are the causes of the American Civil War?

Immediately before the civil war, confrontation was growing in the country. One of the reasons was the high taxes on imported goods. But slavery in the northern states was probably the main reason. Slave labor was very popular at that time. There was also a lot of controversy in society regarding the constitution of each of the states. There was a lot of controversy over whether the new states would be free or slave states. Lincoln declared all states free of slavery. This was the reason for the start of the war.