The Constitution does that. So long as a slave is held by the laws of a state, the constitution requires the slave must be surrendered back to the person to whom his labor is due.
The article you cite only applies to fugitive slaves.
Which is pretty much any slave trying to get out of slavery, isn't it? Dred Scott for example.
It does not address the ability of a territory or a state from making ownership of slaves illegal within that territory or state.
It addresses it insofar as the authority of either the state or territory must comply with the requirements of article IV, to give the slave back to the person to whom his labor is due.
How are you going to free a slave when the constitution specifically says you can't pass a law to do it?
Let's try a thought experiment. A Slave owner brings his slave into one of the territories and puts him to work chopping trees or something. The Slave leaves. The Slave owner finds him. What are the authorities going to do? Tell the slave owner to let him go, or do what the constitution requires they do in such a circumstance?
Where do you see wiggle room in this?
It is entirely legal for the Territory of New Mexico or Dakota to make ownership of slaves by residents of that territory illegal.
I'm just going to punt on the citizens or residents being prohibited from owning slaves. I'll just give you that one, because I can see some reasoning behind that. It still does nothing about non residents from states that hold a slave in bondage.
But they do have a legal responsibility to return a runaway slave if the owner shows up and claims that slave.
And there it is. So how do they prohibit slavery in the territory? They can persuasively bar their residents/citizens from owning them, but they can't free them when non residents/non citizens own them.
At least not without running crosswise of Article IV, Section 2.
“The Constitution does that.” only in the case of a escaped slave. The territorial law can prevent you from residing in the territory and owning a slave in that territory.
“How are you going to free a slave when the constitution specifically says you can’t pass a law to do it?” States are free to pass law outlawing the ownership of slaves in that state. The Supreme Court acknowledges that right. That means a person residing in that state cannot legally own a slave. These laws have nothing to do with “freeing” slaves, they prevent ownership in the first place.
“Let’s try a thought experiment.” The owner of the slave can be jailed for bringing that slave into a territory where ownership of a slave is against the law.
“It still does nothing about non residents from states that hold a slave in bondage.” As long as they do so outside of the states boundaries. Once they bring a slave into a free state they may be arrested for violating state law. This is the primary reason that the owners of escaped slaves would not appear personally in a free state to claim the slave. They would send an agent. That agent was not the owner of the slave, so he did not violate the state law against owning a slave in the state. The State was required by the Fugitive Slave Act to turn the slave over to the agent for transportation back to the owner. Another way to circumvent a state law against ownership of a slave was to pay him or her, while in that state. Thomas Jefferson did this to skirt French laws against slave ownership in France.
DiogenesLamp #226: "The Constitution does that.
So long as a slave is held by the laws of a state, the constitution requires the slave must be surrendered back to the person to whom his labor is due."
It's not clear to me precisely where DiogenesLamp goes beyond what even Dred-Scott claimed, but clearly Northerners in 1860 feared Dred-Scott would allow Southern slave-holders to bring their slaves North to take away jobs from free men.
DiogenesLamp goes even further to claim that's just what Founders intended by their Constitution, even though none said it or acted so at the time.
Regardless, DiogenesLamp's argument is without merit.