Long Term Causes of the Civil War / Triggering Event
The start of the Civil War was caused by social, economic, and political factors. It seemed like the north and south were always competing with each other. Economically, it was the industrial north vs. the agricultural south. Politically, it was the Union north vs. the Confederate south. Socially, it was the free north, who didn't want slaves, and the non-free south, who wanted slaves. There were so many differences, that eventually compromise didn't work, and war broke out.
The two triggering events of the Civil War were Abraham Lincoln's election as president, and when Fort Sumter is attacked. Many states withdrew from the Union once Lincoln was elected.