No Money, No Job

While data on the very poor is limited and subject to challenge, recent studies have found that as many as one in every four low-income single mothers is jobless and without cash aid — roughly four million women and children. Many of the mothers have problems like addiction or depression, which can make assisting them politically unpopular, and they have received little attention in a downturn that has produced an outpouring of concern for the middle class.

Poor families can turn to other programs, like food stamps or Medicaid, or rely on family and charity. But the absence of a steady source of cash, however modest, can bring new instability to troubled lives.

One prominent supporter of the tough welfare law is worried that it may have increased destitution among the most disadvantaged families. “This is the biggest problem with welfare reform, and we ought to be paying attention to it,” said Ron Haskins of the Brookings Institution, who helped draft the 1996 law as an aide to House Republicans and argues that it has worked well for most recipients.

“The issue here is, can you create a strong work program, as we did, without creating a big problem at the bottom?” Mr. Haskins said. “And we have what appears to be a big problem at the bottom.”

He added, “This is what really bothers me: the people who supported welfare reform, they’re ignoring the problem.”

The welfare program was born amid apocalyptic warnings and was instantly proclaimed a success, at times with a measure of “I told you so” glee from its supporters. Liberal critics had warned that its mix of time limits and work rules would create mass destitution — “children sleeping on the grates,” in the words of Senator Daniel Patrick Moynihan, a New York Democrat who died in 2003.

But the economy boomed, employment soared, poverty fell and caseloads plunged. Thirty-two states reduced their caseloads by two-thirds or more, as officials issued press releases and jostled for bragging rights. The tough law played a large role, but so did expansions of child care and tax credits that raised take-home pay.