Permanent Fall in Potential Output

Mark Thoma contemplating Bernanke and DeLong&Summers.  He wonders if the current high level of long-term unemployment is cyclical or structural.  In other words, reduced (aggregate) demand or worsening mismatch between workers' skills and employers' requirements.

I wonder how either is possible as permanent shocks.  People still like (buying) their stuff, and it's hard to imagine that employee/employer matching has suddenly become severely worse.  I think we're still seeing the effects of financial constraints from the recession; it seems to me like a lot of inertia is involved, and we need to rethink how to attack these problems.