No it wasn't. So neither side had the right to take any unilateral action that could infringe on the rights and interests of the other. The only reasonable outcome was negotiation towards a settlement. Unfortunately the South wasn't interested in negotiation.
The legal right to own slaves in this country was a fact before the Constitution was even conceived, so the federal government had no say-so on the issue of slavery in the states where it existed.
As Lincoln made abundantly clear on many occasions. But Lincoln also made it clear that be believed the Taney court was wrong when it ruled that Congress could not legislate slavery in the territories.
After the election of Lincoln, the South's choice was to leave the Union, or stay and let the federal government collapse their agriculturally driven economies.
How? If Lincoln couldn't interefere with slavery in the states where it existed then how could he collapse their economy?
Some choice.
The decision for war certainly didn't work out for the South now did it?
Well...except for the small matters of;
1) No mention of perpetual Union or authority concerning the matter of secession in the Constitution, and
2) Any State was equal to any other State, but ALL were superior to the general government, as that government was a creation OF the States.
That which you create, you have a right to control. It's been there since Blackstone.
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But Lincoln also made it clear that be believed the Taney court was wrong when it ruled that Congress could not legislate slavery in the territories.
Again, it's that creation thing. While it's true the general government has the authority to legislate for the territories, there was no legislative authority over the legality of slavery, so it could not make territorial laws more restrictive than those in the States. It was for the People to decide.
2. [I]t is the opinion of the Court that the act of Congress which prohibited a citizen from holding and owning property of this kind in the territory of the United States north of the line therein mentioned, is not warranted by the Constitution, and is therefore void;
Dred Scott v. Sandford
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If Lincoln couldn't interfere with slavery in the states where it existed then how could he collapse their economy?
By using the morality of slavery as a springboard to force an involuntary Union of States to the detriment of those in the South where slavery existed, perhaps?
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The decision for war certainly didn't work out for the South now did it?
Well, with this giant stinking carcass of a pig that Congress has hanging over our heads, I'd have to say we all lost.
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BTW: Letter to Erastus Corning and Others
Abraham Lincoln June 12, 1863 Executive Mansion, Washington
The resolutions promise to support me in every constitutional and lawful measure to suppress the rebellion; and I have not knowingly employed, nor shall knowingly employ, any other. But the meeting, by their resolutions, assert and argue, that certain military arrests and proceedings following them for which I am ultimately responsible, are unconstitutional. I think they are not. The resolutions quote from the constitution, the definition of treason,
If you show me your definition of Constitutional treason, I'll show you mine. :-)