Only after the US Supreme Court's bizarre Dred-Scott decision in 1857.
Before that everyone understood that slavery was a matter for individual states themselves and for the US Congress to rule over territories.
Before Dred-Scott that was not even controversial.
What was bizarre about it is that it took till 1857 before someone in Authority finally put their foot down against states ignoring Article IV, Section 2.
Before that everyone understood that slavery was a matter for individual states themselves and for the US Congress to rule over territories.
Well they understood incorrectly. Article IV section 2 would have to apply wherever the US Constitution held jurisdiction, and since it had jurisdiction over the territories, it would have had to apply there too, despite some people thinking to the contrary.
Before Dred-Scott that was not even controversial.
Before Trump pointed out that Sanctuary Cities were a defiance of Federal law, they weren't controversial either.
Before Jeff Sessions pointed out that "Marijuana dispensaries" were a violation of Federal law, they weren't controversial either.
The fact that some people have ignored violations of federal laws because they don't like them is only controversial when people point out that they are violating Federal law.