The rebelion in which a number of southern states announced that they were no longer subject to the Constitution, seized federal facilities and raised an army to protect a large area of the United States that they now claimed was in fact a different country. Maybe you've heard about it. It was in all the papers.
The fact that you act all shocked that someone might have objected to this is simply laughable.
That was all in response to the north preparing to wage war against the south. The south was protecting themselves form the war of northern aggression, as you liberal south hating bigots clearly point out the north was waging.