there is a reason why it's called the Union...
The Union never considered any state as seceded from the Union. Therefore, since the United States never ceased to exist it never left !!
No state seceded from the Union in 1880. The first state to secede from the United States was South Carolina, which did so on December 20, 1860, leading to the Civil War. The year 1880 is notable for other historical events, but it did not witness any state secession.
Existing states did not. But the Western counties of Virginia seceded from Virginia when that state voted Confederate. The new state of West Virginia joined the Union in 1863.
They seceded from the USA, because they knew that Lincoln would not allow any new slavestates. They began to take steps to secede from the Union.
Robert E. Lee He disapproved of secession, and asked the General-in-Chief of the Union Armies whether he could stay neutral - to which he got a scathing reply. ("We don't want any fence-sitters!") When Virginia seceded, he declared that he could not draw his sword against his beloved home-state, and resigned from the US Army to join the Confederates.
It means it removed itself from the United States of America, and became independent - anticipating that other states would join them in a new nation. Congress ruled that this was treason. But the Confederates claimed that the Union had started as a voluntary federation, and that any state was free to secede from it.
No. Until 1975, Vice Presidents were not replaced if the office became vacant for any reason.
The Union did not conquer any state.
It appeared to mean that slavery was protected by the Constitution, and could not be banned from any state of the Union.
The election of Lincoln in 1860. He would not allow any new slave-states, so the South knew they would always be outvoted in Congress.
Because the newly-elected Lincoln would not allow the creation of any new slave-states. So the South was doomed to be outvoted in Congress.
The mountain people had always felt different from the coastal communities, and they didn't approve of the secession. So in turn, they seceded from Virginia, to form their own State of West Virginia, which joined the USA in 1863.