Explaining the unique characteristics of this unbalanced recovery is more like 'Murder on the Orient Express' than finding a smoking gun in somebody's hands. There are a lot of suspects.
Folks are coming back into the labor market, but they're not finding jobs there. The tepid pace of job growth was too low to keep unemployment from rising. We're looking at a fairly weak recovery, at least initially.
As jobs become more available, people are no longer finding themselves stuck as long in unemployment.