Yes, I agree. In 1860 this is exactly what you had, a dispute amongst the states in the various sections. At this point I'm suggesting that one or more states could have taken their grievance to the US Supreme Court and obtained a favorable ruling from it on the constitutionality of seccesion. This could of happened even before the newly elected president took office.
Instead, the confederates fired on the US Flag and suffered the consequences.
Even under the circumstances of this possibility, no guarantee existed that Abe Lincoln would honor the ruling. He willfully ignored other court rulings in the same time frame on the grounds that he did not like their outcome, most notably the U.S. Circuit Court ruling in Ex Parte Merryman.
It is also a matter of history that the confederates thoroughly made their case for constitutional secession within the framework of the 1860 government. They did so at length before the Congress.
Instead, the confederates fired on the US Flag and suffered the consequences.
As I have noted previously to you, your reasoning in this statement suffers from severe moral and logical flaws. You chose not to respond previously and this case may be no different, but the issue still remains. By asserting that the south "suffered the consequences" of the actions at Fort Sumter, you imply that what happened over the next four years was a necessary result of that act. It is akin to rationalizing all conscious act, and with it guilt, on the part of the north by asserting little more than "the south made us do it" to justify the brutalities of the war they waged. Much to the contrary, the sins of war committed against the south were not a consequence of Sumter but of the conscious choices of the north to sin in the way they waged that war. As I noted previously, just as is true of the south, The Lincoln had untold many courses of action he could have taken in 1861. The decision of the northern government's reaction to secession was not in southern hands though. That decision, upon which the decision of war and the manner in which that war was to be waged and rested, belonged to The Lincoln. Out of untold many paths ranging from varied scales of war to peace and diplomacy, he chose to pursue the bloodiest one.
That's completely illogical. They very obviously did not question the constitutionality of secession, therefore they had no "grievance" regarding it's constitutionality to take to the Court. If the States still in the union had a problem about it, then they should have taken it to the Court. The new england states obviously didn't question the constitutionality of secession, they flirted with the idea more than once. It was not a new idea.