The man was Robert Toombs.
"The firing upon that fort will inaugurate a civil war greater than any the world has yet seen. Mr. President, at this time it is suicide, murder, and will lose us every friend at the North. You will wantonly strike a hornet's nest which extends from mountains to ocean, and legions now quiet will swarm out and sting us to death. It is unnecessary; it puts us in the wrong; it is fatal."
"The firing upon that fort will inaugurate a civil war greater than any the world has yet seen. Mr. President, at this time it is suicide, murder, and will lose us every friend at the North. You will wantonly strike a hornet's nest which extends from mountains to ocean, and legions now quiet will swarm out and sting us to death. It is unnecessary; it puts us in the wrong; it is fatal."
And he was absolutely right. It's a pity their arrogance got in the way of common sense.