"I trust you won't think I intend the comparison beyond this basic point -- the Declaration cannot mean only that groups of "sincere" people have the right to establish whatever form of government they sincerely want."
PRECISELY so you wouldn't say this:
"You're not really suggesting that the South's decision to peacefully withdraw from the Union is in any way comparable with Hitler's decision to murder millions of Jews, are you? Perhaps not. But you should be more careful in your analogy."
My apologies.