USA has always been scared of applying real consequences for fear of losing popular support. Jefferson and Adams knew slavery was wrong. Adams knew it was wrong and abhorred it. But couldn't do anything because of that reason and the need unite the States of a new nation. Same after the Civil War, healing a fractured nation and all that. Even leading to the Civil War there were Missouri and 1850 Compromises. And it goes on and on. United States of Compromise.

But that would have been lead to even more consequences from the donors, who pretty much treated the democrats as useful idiots at best.

That too