“Revolutionists are heroes if they win, and traitors if they lose.”
The south never had any chance of winning. They made a stupid choice to rebel.
I strongly agree with your second sentence. They were stupid to rebel.
Strongly disagree with your first sentence. For a cause that never had a chance, they came remarkably close to succeeding on several different occasions.
It’s my personal opinion that had any other man been in the White House, the country would have split up.