An anti secession individual has three choices; start a mini war inside of the newly formed country, leave, or STHU. Most leftist a libertarians being pansies will probably go for option 3. Again you need a history lesson and a civic lesson. States rights is real and the secession is real, and it is done on a state level.
You are talking pure theory, and it's pure wishful thinking to believe that a referendum would accomplish anything. We are living in a very, very different country than the US of 1861. If you want to talk history lessons...I mean, you do know what happened last time this was tried, right? Do you suppose it would work out better in round two, with a population that dines on a steady diet of apathy and "Dancing with the Stars"?