But in the case of abolitionism, the moral arguments against slavery came first, decades earlier.
Those are what caused Northerners to outlaw slavery in their own states and in western territories.
But Northerners were tolerant of slavery in the South and in their national political parties.
What united a majority of Northerners behind Republican antislavery ideas was the perceived threat of explanded slavery after the SCOTUS 1857 Dred Scott ruling.
Their opposition was both moral & Constitutional before it was economic.
The combination is what turned many Democrat states in 1856 to Republicans in 1860.
Sure they did, and all confined to a small contingent of kooks who are little different from "transgender rights" types today. Till it became in their economic interest to embrace these ideas, they simply ignored them.
When they saw that they could use them to further their own economic interests, they did.
Those are what caused Northerners to outlaw slavery in their own states and in western territories.
Dominant factor was not the immorality of slavery. The dominant factor was hatred of black people, and hatred of slaves competing with laborers for work. The last thing anyone cared about was the immorality of forcing black people to work.
What united a majority of Northerners behind Republican antislavery ideas was the perceived threat of explanded slavery after the SCOTUS 1857 Dred Scott ruling.
As I have pointed out before, Dred Scott expanded nothing. Dred Scott merely reiterated what the laws and agreements to create a constitution actually said, but which northern states had simply been ignoring for decades.
Article 4 pretty much means you can't keep slaves out of a state because to do so would deny the citizens of other states the immunities and privileges they deserved when the all the states agreed to make a compact with other slave states.
Dred Scott just simply signaled, "Enough of this pretending you can keep slavery out of your state. You can't. "
If they didn't want to abide by their agreement to allow the Union to be a slave Union, they should not have made that agreement.
Pretending they could restrict something they agreed to was disingenuous, but modern liberals do it all the time. It is simply what they do.