The United States once had a welfare program — Aid for Families With Dependent Children — that provided cash to families in need, but A.F.D.C. was hardly generous. Not only were the benefits paltry, the incentives were perverse: If you worked, you frequently lost most or all of your benefits. According to calculations by the Center on Budget and Policy Priorities, A.F.D.C. pulled only 10 percent of children out of poverty in the 1990s.

Even so, many argued that without a work requirement, the program encouraged poor people to remain on welfare. In 1996, legislation put forward by congressional Republicans and ultimately supported by President Bill Clinton ended A.F.D.C. — “welfare as we know it” — and put Temporary Assistance for Needy Families in its place.

But the welfare payments to families with children under T.A.N.F. — in part because of the program’s rules about work and looking for work and in part because the time period during which you can receive welfare is capped — reach a much smaller number of families than A.F.D.C. did. According to the Center on Budget and Policy Priorities, only 23 out of 100 poor families receive any T.A.N.F. benefits at all. In some states, which set their own rules for eligibility, remarkably few families get T.A.N.F. payments.

One result, according to the social scientists Kathryn J. Edin and H. Luke Shaefer, is that in 2011, 1.5 million families with children lived on $2 per person a day. Though food stamps help ease the burden, they are inadequate. To survive, these families depend on food banks, collect aluminum cans for refunds, do the occasional odd job and live in crowded, unsafe quarters.

This is not to say that America has not tried to reduce poverty. Besides food stamps, the earned-income tax credit and the child tax credit also aid poor parents substantially. The problem is that these programs still leave the rate of childhood poverty unconscionably high.