The most promising trend in the labor market in the first three months of 2014 had been workers returning to the job market. Some 1.3 million more Americans counted themselves as either having a job or looking for one in March than in December. That represented the strongest three-month gain in the size of the labor force since the boom times of early 2000.

A dynamic that seemed — maybe, possibly — to be taking shape for 2014 was that of some of the millions of people who had given up on even looking for a job during the recession and the slow recovery were finally returning. That trend might have acted as a floor underneath the overall unemployment rate. People returning to the work force might not find a job immediately, joining the rolls of the unemployed, but it would be good news for the long-term prosperity of the American economy.

The details of the April job report, though, threw serious cold water on that proposition. The number of people in the labor force fell by a whopping 806,000, wiping out the February and March gains and a bit of January as well. The labor force participation rate fell by 0.4 percentage points to 62.8 percent, returning to its December level.