Slavery was actually supported in the Constitution (Hence the South's claim of states rights to slavery), ie each slave was counted as 3/5 of a free person, for population count which determined the number of congressional house members per state, and electoral votes for presidential elections. A sop to the southern states at the Constitution's drafting because winning freedom from Britain needed the combined effort of all 13 original colonies and was considered more important at the time. The friction started after more territories applied for statehood and the North wanted to prevent slavery from expanding into these new states. The North (in particular, Lincoln) was content to allow slavery in the original slave states, realizing that it would eventually wither on the vine. There was a compromise enacted to allow these border states to vote on slavery, and with all the ballot stuffing by cross border Southerners, and the subsequent violence by opposing sides the tensions mounted to the boiling point. The Republican's improbable Presidential election victory by Lincoln was the spark that set off the South's secession.


One must realize that our contemporary view of equality was not commonly shared by even the most vocal abolitionist of that time period.