"That amounts to tidily squat!"
The Constitution amounts to much. The Constitution IS the nation, and the Nation IS its Constitution.
Whether or not they knew what States would ratify, they all ratified "We the people", and called it "the supreme law of the land".
A contract can be disolved by mutual agreement, or violated by one of the parties. It cannot be disolved by one of the members, or by part of the members acting alone. Such violations of contracts result in litigation.
In the case of the violation of the contract of Union known as the Constitution, violent litigation ensued.
Requiem æternam dona eis, Domine; In memoria æterna erit justus, ab auditione mala non timebit.
The Constitution IS the nation Actually the nation is the people. The country is the land they live on, bounded by their borders; and the Constitution is the compact made among them....by consent.
And if you read the little human rights document known as "The Declaration of Independence", you'll see that sometimes, "when in the course of human events", such bonds are unilaterally broken.
It asserted in that document that this is a right of free peoples, whenever a government crosses the line into tyranny.
Killing 1/4 of the White males in the South, virtually all of them descendants of the original American colonists, in pursuit of an abstract claim about violating a contract, pretty much qualifies as violent Tyranny, much more than imposing a lousy 3% tea tax or whatever it was.