That really is not clear from the statement: "We have yet to see how the US reacts when a massive section of it wants to secede," which is obviously false.
It's not false because we don't know what the reaction would be if this happened today. The reaction of people 160 years ago is not at all predictive of what would happen today. Especially if the issue was not a moral one as it was 160 years ago.
Its obvious falseness is usually a hint that there are contextual conversational modifiers that are implicit. Conversationally, if your objective is information exchange, it is usually more productive to ask for clarification than to refute one interpretation.