I'll chip in with a quick Thomas Jefferson quote. I'm at work, so can't get you the exact citation, but it is along the lines of, "Slavery is like holding a wolf by the ears: you might not like it, but you dare not let it go." I think this quote is a good encapsulation of the political mess that slavery represented in the US in the late 18th century. On a moral level, while men like Thomas Jefferson might not have approved of slavery, they saw it as something that was connected to larger consequences for the country as a whole. In other words, Jefferson was implying (quite correctly, as the Civil War proved) that simply abolishing slavery was impossible without dramatic consequences for the young nation. Sure, you could just let the wolf go, but what then? Were a President to unilaterally abolish slavery (were that even possible), a Civil War would have almost certainly broken out just as it did when Lincoln was elected (and that's when only a suspicion that he MIGHT abolish slavery was all that was in play). In short, I think you can tip your hat to Jefferson for assessing the situation correctly (Civil War = a wolf eating your face).