New jobs numbers will be released Friday morning, and they are expected to show, at last, some significant creation of new jobs. A cheer will go up at the White House at this sign that the long climb out of the recession's unemployment hole may have begun.

But any cheering will be tempered by nagging concern over an insidious problem lurking within the numbers: the startling number of Americans who have fallen into the ranks of not just the unemployed, but the long-term unemployed.

The...