And our government obtained that authority, as authorized by its Congress, and ratified by the people of the several states. Once the Constitution was ratified, it had supreme authority.
If those people want to leave that government (and they comprise a large enough and unanimous area to do it) then they should be allowed to.
It's always fun to make up rules as you go, but that isn't what was agreed to. Some folks say each individual ought to be able to "secede". What makes a group "large enough." What authority does that give them? Sorry, but the truth is our government obtained its authority, and the people and states were bound to it.
And if the government says that all your earnings and your children are to be confiscated and you are to be sold into chattel slavery well then so be it because after all, we are bound to the government.
This is exactly what the south was trying to avoid. The end of states rights, the end of people being able to decide for themselves how to live without big brother looking over their shoulder.
With the exception of national defense and perhaps foreign relations, everything the government touches turns to crap.
I still think if a state decides to leave the union they should have the freedom to do so. Now, instead of having one sub-race being held in slavery we had the entire south held in slavery.