Just for the pts the answer was brothers
Social tensions were similar to ethnic and religious. Immigrants wanted to go westwards and establish new states, and locals wanted to get land and become politicians in new states, which caused problems. For example, Mormons were religiously prosecuted constantly and had to go as far as Utah in the end. Political tensions were party related and slavery related. They grew out of ideas on whether new states should be slave states or not.
They believed that the north would very easily squash the confederates and thought it might be an amusing show.
They did cause they were terrible people who’s land and resource were failing