“But they can’t take the territory of the sovereign people of the United States without their consent.”
There was no “sovereign people of the United States” at that time. There were a number of sovereign states, that had formed a political union. In each state that seceded, the people of the state gave their consent, either through popular vote, or through their elected representatives.
This notion of a “sovereign people of the United States” is a result of the fallout from that war. Before that, everyone properly understood that, if the individual states were not themselves sovereign, then they never would have had any power to form the “United States” in the first place.
Wrong.
The Declaration of Independence was done in the name of all the people of the American colonies, and the war for independence was prosecuted by all, as a body.
The Articles of Confederation AND PERPETUAL UNION, and thereafter the Constitution of the United States, established us as one nation, under God.
“We the People of the United States...”
I think most people "get" that you guys wish to endlessly debate your "theory of secession", and some even understand that your "theory" is false, because our Founders originally intended that secession must not come "at pleasure" but only from mutual consent or, in effect, a serious breach of compact.
And neither condition existed in December 1860.
But what only a few seem to grasp is that this "debate" is utterly irrelevant -- because Deep South declarations of secession did not cause Civil War.
Neither did forming a new Confederacy cause Civil War.
And neither did dozens of Confederate provocations in seizing Federal forts, ships, arsenals and mints.
What started Civil War was the Confederate military assault on Federal troops in Federal Fort Sumter, followed by their formal declaration of war against the United States, and sending military aid to pro-Confederates in Union Missouri.
In his First Inaugural Address (March 4, 1861) Lincoln announced to the Confederacy that they could not have a war unless they themselves started it.
So Jefferson Davis immediately ordered preparations for the assault on Fort Sumter.
Your arguments over secession theory are irrelevant to actual history.