The northern states were beginning to end it as the Revolution was fought, and many believed all the states would gradually end it when the Constitution was being debated. (www.civilwartalking.com) But as things developed, they didn't. The main cause of war wasn’t the North and South’s differences. It was all caused by slavery.
Things were going downhill for decades before the American Civil War broke out. By the 1850s the radicals in the South wanted all limitations on slavery removed; they wanted to impose and intervene in the North to enforce what they consider their rights. They wanted to roll back the Compromise of 1850 and the Missouri Compromise. The radicals in the North, wanted to restrict slavery; they wanted to end slavery. The real outer fringe on both sides resorted to violence. People North and South were forced to pick sides as year after year as intense political conflict continued.
What was needed to resolve this without war is compromise. What we saw in the 1850s is a failure to compromise, a hardening of positions, and a deliberate inflammation of differences. The Civil War came about because of the total failure of the politicians of that day to work out a compromise. (www.differencebetween.net)