and I would like to know if any Southern State legislatures have rescinded their declaration to leave the Union and join the Confederacy?
All of the seceding states had to petition to rejoin the union. South Carolina, the first state to leave, was the last to be readmitted.
The North was not "invading" the South. We ARE all one nation.
You have it completely backwards. The concept that we are all one nation comes from the Civil War. Before then, most people's first allegiance
was to their state and not their nation.
Robert E. Lee was a US Army officer at the start of the Civil War. He had taken oaths to defend both the US and the state of Virginia. He was activated by the Federal government and Virginia at the same time and had to decide which oath meant more to him. And this isn't a guy who took oaths lightly. He surrendered and was paroled by Grant
before the war ended. When the Confederacy surrendered a few weeks later, Lee was already home in Richmond with his family. He gave his word to stop fighting and he actually did.
Probably the starkest example of how important the concept of state was back then, though, came when Lee ordered his army to move north out of Virginia. Men deserted rather than follow that order. They had joined the Confederate army to defend Virginia and they had absolutely no intention of invading another state. They risked execution over their love of state above country.
It was Ken Burns who put it best. He said that before the war, people said "The United States are ..." After the war, they said, "The United States is ..."
You're applying the most important lesson of the Civil War to people's actions before the Civil War. That's like saying the US shouldn't have fought in Vietnam because they knew it would be another Vietnam.