In a way it was. If the Confederacy had won it’s independence, the Union as it existed before January 1 1861 would have died.
So I wonder if it works both ways. So when a territory was admitted to the Union, the Union as it existed prior to that territory becoming a state would have died. Right?
So? The British Union as it existed before July 4, 1776 died, but what remained of it went on to be more prosperous than it had ever been in it's entire history. So did the part that broke away.
And we still celebrate the death of the British Union as it existed before July 4, 1776.