I would argue that one of the reasons that legitimate questions of peaceful secession get lumped in with civil war era secession is that actual Neo-Confederates WANT it that way -- any modern-day talk of secession (including states that are nowhere near the south) and they start a "the south was RIGHT!" thread on the internet, arguing that the civil war had nothing to with slavery, and wave the confederate flag around at Tea Party events. This does NOT help our side. (not to mention they totally accept the kool-aid from the mainstream media and the left that segregation-era Democrats were "the conservative party back then")
Modern-day talk of secession may be fun, but it is not something actually on the table, unless one resides in the confines of Candyland.
Kick out Hawaii and Vermont (free trade with both) and eject those foreign devils, Sanders and Leahy!