Actually the hard challenge of secession is pure survival. Some sort of tipping point event has to make such a course of action seem necessary to the majority. In 1860 it was the realization that John Brown was funded by some of the richest men in America a such as Gerrit Smith. The refusal of several states to extradite members of brown's band and the brilliantly executed PR campaign by abolitionists to present brown as a Christ lick figure rather than the first modern terrorist made Lincoln's (who was no abolitionist by a long shot) election the tipping event. People have to believe their livelihoods and lives and the families lives are in danger to embrace such a course. Once any group tries this even in a ragged and disorganized US of the future the federal authorities are going to use the Lincoln Playbook and stigmatize the event as treason and the agents of it terrorists and all the force of the US Government will be used on that region. Any group defying the feds better be well versed in highly disciplined civil disobedience (which does not mean absolute non-violence) as it is the only way to frustrate such actions as would be taken. This takes real guts as , unlike the civil rights protesters the media will be with the Feds and portray secessionists as racist cracker KKK types who want to murder blacks and gays and enslave women. This would be a hard fight and the planing better start know and try to convince a cadre of people to think through the actions necessary and quietly recruit substantial citizens and military vets if possible. In spite of our culture and government being rotten with moral corruption and a really vicious sort of materialism a great many Americans nurture beliefs that the US government is something it most certainly is not. Getting them to see what is so is the first battle.