Some say simplistically that the Civil War was fought over slavery. Unfortunately, there is no "simple" reason. The causes of the war were a complex series of events, including slavery, that began long before the first shot was fired. Some of the reasons that caused the Civil War were Constitutional issues, tariffs and nullifications, economic changes, the breakdown of the political system, and finally slavery. .
People argued about the meaning of the Constitution since the beginning. From a legal standpoint, the document is a contract between the people of the United States and the federal government, detailing the powers and responsibilities of each. In 1828 Vice-president John C. Calhoun said that if a state felt a federal law extended beyond the Constitutional rights of the government that state had the right nullify the law. This concept dated back to the Articles of Confederation. President Andrew Jackson felt the federal government was the highest authority and that the states had to abide by its law. This became a clear issue when during Jackson's term as president South Carolina threatened to secede when more tariffs were passed. The only thing that averted tragedy here was the fact that Henry Clay brought a compromise to that table that both sides accepted and were willing to live with. As you can see there clearly were tensions about the constitution even before the civil war had started. .
The Panic of 1837 brought the entire factory and industrial economy of the US to a halt. The disparity between northern and southern economies was clearly seen in this crisis. Before and after the depression the economy of the South was very strong. Southern cotton totaled 57% of all American exports before the war. Many people in the north felt resentment for the fact that the south had been spared by this panic. The Panic of 1857 was another incident in which the north was devastated and the South was virtually untouched.