Drudge played up this Washington Post piece a few days ago that showed the Army war-gaming on paper a Tea Party militia take-over of a South Carolina town in 2016. Something along those lines is plausible, but would most likely take place on a smaller scale than Darlington; a small town in Idaho or Montana would be more likely be a candidate for an armed succession.
However, my bigger concern for a 2016 nightmare scenario is whole states succeeding. If we take a pessimistic economic and cultural projection out 4 years, runaway spending and higher taxes coupled with an increase in political violence both from Occupiers and renegade rightists could have some states declaring independence rather than stay a part of a downgraded, deteriorating US. A governor and state legislature could declare independence, call up the National Guard and dare Washington to invade.
What they might want to also roll-play out is what 2016 might look like under a Romney administration. If we extrapolate things like the Occupiers, Wikileaks and Anonymous, a disgruntled and emboldened anarchosocialist left could make the Web unusable and declare more liberal cities independent. A literal People's Republic of Santa Barbara (for example) might take shape, and if Jerry Brown opts to bid them adieu without a fight, Marines might have to head north from their San Diego-area bases to restore US sovereignty.
Even a second Obama term might see some of that. If Obamacare needs to be scaled-back some as it gets rolled out, the left might see that anarchic action would bring better results than democratic efforts. Couple that with Obama's less-than-leftist take on drones, Gitmo and possibly Iran and Syria if we fast forward a year or two, the hard left might see Obama as Tweetledummer and act accordingly.
Yes, I hear you in the back right-good bye and good riddance. No, they'll likely make a mess of their new republic and be begging back in a decade or two later.
Thankfully, the modern left doesn't like guns as a group; their pacifist streaks makes them bad insurgents. For instance, one has to be thankful that today's shooter at the Family Research Council wasn't a well-prepared gun nut like the Aurora Joker.
However, they can make things miserable to a point where giving in to their demands, if feasible, might be the path of least resistance; that has often been the case in France. The ongoing student protests in Quebec have the government struggling to make modest moves to increase tuition; such street action, if rewarded, can become common.
We live in interesting times. Pray that they don't get too much more interesting.