One might also make the observation that “Might makes Wrong” when you look at how the southron fire-eaters attempted to muscle their way into a political solution and got their asses handed to them as a result.
Or if you prefer, “Wrong makes Weakness.”
Prince Albert on his deathbed, knowing that a divided US could be exploited by England, still exacted promises from the two men likely to be Prime Minister that they would not support the slave power. He saw it as a moral duty.