Most lost cause losers recognize the foolishness of your “argument” and at least attempt to proffer some sort of hackneyed justification for rebelling. It’s common to hear them bleating about enduring “tyranny” - even though the south dominated the government for most of the United States’ 70 years.
The Founders recognized the difference between natural law and codified law. None of them accepted the notion of unilateral secession or dissolution “at pleasure”.
The "cause" which was lost by that war was that of a nation founded on the principles of natural law. Abraham Lincoln was the man who rebelled against a nation that was "four score and seven years" old, and created by the very same act as the Confederacy. The confederates were the ones keeping true to the founding principles, it was the Union which had rebelled.
That is completely wrong. If you go back to the 1787-88 debates in the New York, Rhode Island, Virginia, and North Carolina legislatures, you will see many examples of secession discussions. There were several efforts to codify, modify, and place limits on states involved in seceding.
All of these efforts prove the opposite of the statement you made. State legislatures would not make secession illegal, and thus neither did the Constitution.
We do know that 74 years later, that the United States Congress judged secession to be legal....unilateral or not.
12/12/1860 On this date the United States House of Representatives proposed the following Constitutional Amendment:
”Whenever a convention of delegates, chosen in any State by the people thereof, under the recommendation of its legislature, shall rescind and annul its ratification of this Constitution, the President shall nominate and, by and with the advice and consent of the Senate, shall appoint commissioners, not exceeding three, to confer with the duly appointed agents of such State, and agree upon the disposition of the public property and territory belonging to the United States lying within such State, and upon the proportion of the public debt to be assumed and paid by such State; and if the President shall approve the settlement agreed upon by the commissioners, he shall thereupon transmit the same to the Senate; and upon the ratification thereof by two-thirds of the senators present, he shall forthwith issue his proclamation declaring the assent of the United States to the withdrawal of such State from the Union.”.
Since secession was not specifically prohibited by the Constitution, Congress attempted to pass an amendment requiring approval.
It passed the House 154-14. It soon failed as well as at least two more efforts to legislate rules regarding secession.
Efforts were made but unilateral secession was never prohibited by law.