Well, which groups are you referring to? I'll assume for the sake of answering that you mean the Union, the formal United States of America, and the Confederates, the Confederate States of America. While it is still a fiercely debated topic as to the motives and reason behind the war, none doubt that Lincoln's election and the attack on Fort Sumter were the sparks that ignited the most deadly war in American history. The North sought to retain their Union, to preserve the United States as a single, unified country. The South sought to break from the Union, preserving their own interests and their economy, one that they saw as being attack by the North. Despite it being taught that slavery was the main factor of the American Civil War, this is only surface level truth and even slightly revisionistic in nature. The North wanted to end slavery because they saw it as immoral, ignoring how dependent the South were on slave labor and the impacts it would make across the Southern countries of slavery were to be outlawed. Contrastly, the South were too protective of their economy, unable to find a way to survive without slave labor and drunk on the money that it brought them. With both groups never seeking and never finding common ground, a war erupted for the fate of the states.