Some years ago (can't recall exactly when) there was a referendum in Quebec (Canada) asking voters if Quebec should break away from the rest of Canada and become a sovereign country. It failed. There was no indication that if it succeeded that Canada would send troops into Quebec.
And then there's Scotland. A few years ago (2014?) there was a similar referendum there. It failed. Again,there was no indication that London would have sent troops into Scotland if it had succeeded.
I strongly doubt that any state...or group of states...that wanted to break away would be forced to stay through the use of troops or anything like that.
I'm not quite sure what you're referring to here, but if this statement is with regard to the U.S., you might want to see how General Lee felt about it.