When the South seceded they drafted their own Constitution that was very much like our original with an exception. They forbid the future importation of slaves from then on. I found that interesting. I read that in my encyclopedia, I believe.
They did not secede, the only attempted to, get it right....
I just looked in my World Book encylopedia volume 4 and it states this " the states seceded (withdrew) from the government of the Unites States in 1860 and 1861 because they feared that the election of Abraham Lincoln, a republican president, might lead to restrictions on their right to do as they chose about the question of slavery".
Your statement is contrary to this.