I think we can look back at various events from the past few years and see them as trial runs and experiments in crowd psychology.
Athens, Greece? Yeah, the Left can energize crowds and burn down part of a city.
Occupy Wall Street? Yeah, the Left can move a peaceful crowd into a number of locations without unduly upsetting local authorities.
Flash mobs? Yeah, the Left can organize crimes of convenience which are committed by faceless crowds and impossible to chase.
Trayvon Martin? Yeah, the Left can gin up public support for anyone at all, and against anyone at all, and the Left can manipulate racial backgrounds of people so that they can be conveniently labeled as "the bad guy race".
All the ingredients are there. All the training is fresh.
If the Left finds an incident (Trayvon) they could initiate massive peaceful protests (OWS) which, once established, could spark confused over-reaction by authorities (triggered by flash mob violence), which could result in crowd counter-reaction and masive violence and destruction through civil disobedience (Athens).
The stage is set. The powder kegs are piled high. And Obama has a match.
Suing Sheriff Joe-radicle messicans
Boogie dancing about killing UBL-radicle muzzies
Coming out of the closet-radicle homos
This is just the last couple of months, and as you pointed out these are just a few in a pattern of energizing radicals in different groups.
This isn't energizing the base for votes because they loose votes every time they energize these radicals.