The Confederacy, the Southern States, was formed as a result of States seceding from the United States Union. They seceded because they were no longer treated as equals under the Constitution by the Northern States.
"It was not the passage of the personal liberty laws, it was not the circulation of incendiary documents, it was not the raid of John Brown, it was not the operation of unjust and unequal tariff laws, nor all combined, that constituted the intolerable grievance, but it was the systematic and persistent struggle to deprive the Southern states of equality in the Union--generally to discriminate in legislation against the interests of their people; culminating in their exclusion from the territories, the common property of the states, as well as by the infraction of their compact to promote domestic tranquility. (The Rise And Fall Of The Confederate Government, Vol. 1, Jefferson Davis, Da Capo Press Inc., 1990, p. 70)
Quantrill