I have always thought that slavery would at some point become so impractical that it would nearly disappear in practice. I have been less certain it would have ever legally ended in the United States because a Conditional Amendment ending slavery would have been so difficult to pass. This kind of law would make ending slavery even more difficult.\n\nThat was kind of Lincolns view as well. That it was Constitutionally protected where it existed, and there wasn't the votes to change that. So his goal was to create new free states to change that balance. And the South saw long term what that would do with slavery. Texas had just fought a war to escape a country in part because they abolished slavery and they saw what was happening to it in Europe and it's colonies. Obviously the war changed what was possible for Lincoln and moved up that timetable.